WO2012134398A1 - Dispositif ultrasonique sans contact, système ultrasonique sans contact pour déterminer la pression intraoculaire d'un œil et procédé de détermination de la pression intraoculaire d'un œil - Google Patents

Dispositif ultrasonique sans contact, système ultrasonique sans contact pour déterminer la pression intraoculaire d'un œil et procédé de détermination de la pression intraoculaire d'un œil Download PDF

Info

Publication number
WO2012134398A1
WO2012134398A1 PCT/SG2012/000112 SG2012000112W WO2012134398A1 WO 2012134398 A1 WO2012134398 A1 WO 2012134398A1 SG 2012000112 W SG2012000112 W SG 2012000112W WO 2012134398 A1 WO2012134398 A1 WO 2012134398A1
Authority
WO
WIPO (PCT)
Prior art keywords
ultrasonic
corneal surface
elements
frequency
eye
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/SG2012/000112
Other languages
English (en)
Inventor
Jinli Qu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Agency for Science, Technology and Research
Original Assignee
Agency for Science, Technology and Research
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Agency for Science, Technology and Research filed Critical Agency for Science, Technology and Research
Publication of WO2012134398A1 publication Critical patent/WO2012134398A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B3/00—Apparatus for testing the eyes; Instruments for examining the eyes
    • A61B3/10—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
    • A61B3/16—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for measuring intraocular pressure, e.g. tonometers
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
    • A61B8/10—Eye inspection

Definitions

  • Various embodiments relate to a non-contact ultrasonic device, an ocular device comprising the non-contact ultrasonic device, a non-contact ultrasonic system for determining an intraocular pressure of an eye, a non-contact ultrasonic system for determining an information of an eye, a non-contact ultrasonic system for determining a topographic profile of a deformable structure, a non-contact ultrasonic device for actuating a deformable structure, a method of controlling a non-contact ultrasonic device, a method of determining an intraocular pressure of an eye, a method of determining an information of an eye, a method of determining a topographic profile of a deformable structure and a method of actuating a deformable structure.
  • IOP intraocular pressure
  • An elevated IOP is one of the major risk factors associated with the eye disorder glaucoma.
  • monitoring the IOP is one of the factors involved in the management of glaucoma.
  • the current gold standard of IOP measurement is based on the Goldmann Applanation Tonometer, which uses a probe to physically form an indentation on a corneal surface of an individual's eye.
  • the Goldmann Applanation Tonometer and other existing IOP measurement approaches such as pneumotometer and dynamic contour tonometer (DCT) have two major shortcomings. These include (i) the requirement of contact with a corneal surface of the individual's eye and (ii) measurements of the IOP without considering the corneal profile of the individual, which varies from one individual to another individual.
  • a non-contact ultrasonic device may include a plurality of first elements configured to actuate a corneal surface of an eye; and a plurality of second elements configured to emit a plurality of measurement ultrasonic beams on a point on the actuated corneal surface, and further configured to receive a reflected ultrasonic beam from the plurality of measurement ultrasonic beams reflected at the point on the corneal surface.
  • an ocular device may include: a non-contact ultrasonic device.
  • a non-contact ultrasonic system for determining an intraocular pressure of an eye.
  • the non-contact ultrasonic system may include a non-contact ultrasonic device or an ocular device comprising a non-contact ultrasonic device; and a control module in electrical communication with the non-contact ultrasonic device, wherein the control module is configured to determine the intraocular pressure.
  • a method of controlling a non-contact ultrasonic device is provided.
  • the method may include actuating a corneal surface of an eye; emitting a plurality of measurement ultrasonic beams on a point on the actuated corneal surface; and receiving a reflected ultrasonic beam from the plurality of measurement ultrasonic beams reflected at the point on the corneal surface.
  • a non-contact ultrasonic system for determining an intraocular pressure of an eye.
  • the non-contact ultrasonic system may include a topographic profile determination circuit configured to determine a topographic profile of a corneal surface of the eye; a tensional force determination circuit configured to determine a tensional force of the corneal surface; and an intraocular pressure determination circuit configured to determine the intraocular pressure of the eye based on the tensional force and the topographic profile.
  • a method of determining an intraocular pressure of an eye may include determining a topographic profile of a corneal surface of the eye; determining a tensional force of the corneal surface; and determining the intraocular pressure of the eye based on the tensional force and the topographic profile.
  • a non-contact ultrasonic system for determining an intraocular pressure of an eye.
  • the non-contact ultrasonic system may include a topographic profile determination circuit configured to determine a topographic profile of a corneal surface of the eye; a plurality of first elements configured to actuate the corneal surface; a plurality of second elements configured to emit a plurality of measurement ultrasonic beams on a point on the actuated corneal surface, and further configured to receive a reflected ultrasonic beam from the plurality of measurement ultrasonic beams reflected at the point on the corneal surface; and an intraocular pressure determination circuit configured to determine the intraocular pressure of the eye based on the plurality of measurement ultrasonic beams emitted, the reflected ultrasonic beam received and the topographic profile.
  • a method of determining an intraocular pressure of an eye may include determining a topographic profile of a corneal surface of the eye; actuating the corneal surface; emitting a plurality of measurement ultrasonic beams on a point on the actuated corneal surface; receiving a reflected ultrasonic beam from the plurality of measurement ultrasonic beams reflected at the point on the actuated corneal surface; and determining the intraocular pressure of the eye based on the plurality of measurement ultrasonic beams emitted, the reflected ultrasonic beam received and the topographic profile.
  • a non-contact ultrasonic system for determining an information of an eye.
  • the non-contact ultrasonic system may include a plurality of elements configured to emit a plurality of ultrasonic beams on a point on a corneal surface of the eye, and further configured to receive a reflected ultrasonic beam from the plurality of ultrasonic beams reflected at the point on the corneal surface; and a control module in electrical communication with the plurality of elements, wherein the control module is configured to determine a change in amplitudes between the plurality of ultrasonic beams and the reflected ultrasonic beam to determine the information.
  • a method of determining an information of an eye may include emitting a plurality of ultrasonic beams on a point on a corneal surface of the eye; receiving a reflected ultrasonic beam from the plurality of ultrasonic beams reflected at the point on the corneal surface; and determining a change in amplitudes between the plurality of ultrasonic beams and the reflected ultrasonic beam to determine the information.
  • a non-contact ultrasonic system for determining a topographic profile of a deformable structure.
  • the non-contact ultrasonic device may include a plurality of elements configured to emit a plurality of ultrasonic beams on a point on a surface of the deformable structure, and further configured to receive a reflected ultrasonic beam from the plurality of ultrasonic beams reflected at the point on the surface; and a control module in electrical communication with the plurality of elements, wherein the control module is configured to determine positions of the plurality of elements to determine the topographic profile.
  • a method of determining a topographic profile of a deformable structure may include emitting a plurality of ultrasonic beams from a first active group of a plurality of elements on a point on a surface of the deformable structure; receiving a reflected ultrasonic beam from the plurality of first ultrasonic beams reflected at the point on the surface with a first passive group of the plurality of elements; and determining positions of the first active group and the first passive group to determine the topographic profile.
  • a non-contact ultrasonic device for actuating a deformable structure.
  • the non-contact ultrasonic device may include a plurality of first elements configured to emit a plurality of first ultrasonic beams having a first frequency at a surface of the deformable structure; and a plurality of second elements configured to emit a plurality of second ultrasonic beams having a second frequency at the surface of the deformable structure, wherein the second frequency comprises the first frequency and a third frequency, wherein the third frequency is lower than the first frequency, and wherein the deformable structure is effectively actuated at the third frequency.
  • a method of actuating a deformable structure may include emitting a plurality of first ultrasonic beams having a first frequency for generating a first ultrasonic pressure, Pi, at a surface of the deformable structure; and emitting a plurality of second ultrasonic beams having a second frequency for generating a second ultrasonic pressure, P 2 , at the surface of the deformable structure, wherein the second frequency comprises the first frequency and a third frequency, wherein the third frequency is lower than the first frequency.
  • FIG. 1 shows a schematic block diagram of a non-contact ultrasonic device, according to various embodiments.
  • FIG. 2 shows a schematic block diagram of an ocular device, according to various embodiments.
  • FIG. 3A shows a schematic block diagram of a non-contact ultrasonic system for determining an intraocular pressure of an eye, according to various embodiments.
  • FIG. 3B shows a schematic block diagram of a non-contact ultrasonic system for determining an intraocular pressure of an eye, according to various embodiments.
  • FIG. 4 shows a flow chart illustrating a method of controlling a non-contact ultrasonic device, according to various embodiments.
  • FIG. 5 shows a schematic block diagram of a non-contact ultrasonic system for determining an intraocular pressure of an eye, according to various embodiments.
  • FIG. 6 shows a flow chart illustrating a method of determining an intraocular pressure of an eye, according to various embodiments.
  • FIG. 7 shows a schematic block diagram of a non-contact ultrasonic system for determining an intraocular pressure of an eye, according to various embodiments.
  • FIG. 8A shows a flow chart illustrating a method of determining an intraocular pressure of an eye, according to various embodiments.
  • FIG. 8B shows a flow chart illustrating a method of determining an intraocular pressure of an eye, according to the embodiment of FIG. 8 A.
  • FIG. 9 shows a schematic block diagram of a non-contact ultrasonic system for determining an information of an eye, according to various embodiments.
  • FIG. 10 shows a flow chart illustrating a method of determining an information of an eye, according to various embodiments.
  • FIG. 1 1 shows a schematic block diagram of a non-contact ultrasonic system for determining a topographic profile of a deformable structure, according to various embodiments.
  • FIG. 12 shows a flow chart illustrating a method of determining a topographic profile of a deformable structure, according to various embodiments.
  • FIG. 13 shows a schematic block diagram of a non-contact ultrasonic device for actuating a deformable structure, according to various embodiments.
  • FIG. 14 shows a flow chart illustrating a method of actuating a deformable structure, according to various embodiments.
  • FIG. 15 shows a perspective view of a non-contact ultrasonic system comprising a non-contact ultrasonic device, according to various embodiments.
  • FIG. 16 shows cross-sectional views of a method to determine a topographic profile of a corneal surface of an eye, according to various embodiments.
  • FIG. 17 shows a cross-sectional view of a method to determine a thickness at an incident point of a corneal surface of an eye, according to various embodiments.
  • Various embodiments provide an intraocular pressure (IOP) measurement approach, without or with reduced at least some of the associated disadvantages of conventional devices and approaches.
  • IOP intraocular pressure
  • Various embodiments may provide a non-contact measurement approach for the eye, with minimal intervention on the movement of the eyeball.
  • Various embodiments may achieve non-contact with the eye by incorporating an air-coupled approach.
  • the approach of various embodiments take into account a corneal curvature profile and a corneal thickness profile of an eye of an individual.
  • Various embodiments may provide a device, a system and a method for the measurements of ocular properties (e.g. an intraocular pressure and/or a topographic profile of a corneal surface) using an array of air-coupled ultrasonic transducers.
  • ocular properties e.g. an intraocular pressure and/or a topographic profile of a corneal surface
  • Various embodiments may provide a non-contact intraocular pressure (IOP) measurement device, system and method, using an array of air-coupled ultrasonic transducers.
  • the measurement device, system and method may be used for performing in-vivo measurements. As the array of ultrasonic transducers are air-coupled, only ambient air is necessary for performing the measurements.
  • the measurement device and system may include an array of dual frequency air-coupled ultrasonic transducers.
  • the ultrasonic or acoustic beams emitted from the array of ultrasonic transducers are steered and focused through the use of array beam-forming technology. Beam-forming is a technique used in sensor arrays for directional signal transmission or reception.
  • the measurement device and system may include one or more front-end circuits integrated with the array of dual frequency air-coupled ultrasonic transducers.
  • the measurement device and system may also include a control module, a digital signal processing module and a measurement display means.
  • the digital signal processing module may be integrated in the control module or provided as a separate module.
  • the measurement display means may be a display screen or a display unit, integrated with the measurement device and system of various embodiments, or provided separately.
  • the array of ultrasonic transducers may be bonded on glass spectacles or glass goggles (for example on a surface of the glass) and worn or placed in proximity with a corneal surface of an eye of an individual.
  • the array of ultrasonic transducers may be used to measure or determine a topographic profile (e.g. a curvature profile and/or a thickness profile) of a corneal surface of an eye to facilitate measurement of the IOP, with enhanced accuracy. Subsequently, the array of ultrasonic transducers may be used to determine a tensional force of the corneal surface, in order to determine the IOP based on the tensional force and the topographic profile of the corneal surface. Accordingly, the topographic profile, such as the curvature profile and/or the thickness profile of the corneal surface, may be determined before the IOP measurement and are considered when determining the IOP. In various embodiments, the tensional force of the corneal surface may also give a measurement of the tensional force among the corneal structures of the eye.
  • a topographic profile e.g. a curvature profile and/or a thickness profile
  • the tensional force of the corneal surface may be determined using two independent approaches.
  • the first approach is to detect or determine the resonant frequencies of the corneal surface.
  • the resonant frequencies of the corneal surface may be determined from the corneal surface velocity.
  • the second approach is to monitor or determine the impedance of the corneal surface.
  • the impedance may be determined from a reflectance of the corneal surface.
  • the arrangement or configuration of the array of ultrasonic transducers may be provided to cover at least a substantial portion of the corneal surface for determining the intraocular pressure (IOP). This may alleviate or relax the alignment requirement of the array of ultrasonic transducers to the central position of the corneal surface or cornea, thereby improving the robustness of the measurement.
  • IOP intraocular pressure
  • Various embodiments may provide a device, system or method of determining an intraocular pressure of an eye, including an array of dual frequency air-coupled ultrasonic transducers for actuating and sensing the corneal surface or cornea through ultrasonic beams.
  • the array of dual frequency air-coupled ultrasonic transducers includes a plurality of first elements and a plurality of second elements, where the plurality of first elements have a different size or dimensions (e.g. an area) and a different central frequency to the plurality of second elements.
  • Various embodiments may provide a portable device or system.
  • the portable device or system may be used for continual or semi-continuous measurement of the IOP during the periods when an individual's eye remains open.
  • Various embodiments may provide a method of measuring or determining an intraocular pressure (IOP), by determining a topographic profile of a corneal surface, such as a corneal curvature profile and a corneal thickness profile, and detecting the corneal surface resonant frequencies or structural resonant frequencies, in order to determine the IOP.
  • IOP intraocular pressure
  • Various embodiments may provide a method of monitoring a fluctuation of an intraocular pressure (IOP) by monitoring or analyzing variations or changes of amplitudes in the acoustic signals reflected from a corneal surface.
  • IOP intraocular pressure
  • the term 'ultrasonic' as applied to ultrasonic waves mean that the waves have a frequency greater than the upper limit of human hearing (e.g. a frequency greater than approximately 20 kHz). Ultrasonic waves are sound waves and therefore, in the context of various embodiments, the term 'ultrasonic' may be used interchangeably with the term 'acoustic'. [0056] In the context of various embodiments, the terms 'ultrasonic waves' and 'ultrasonic beams' may be used interchangeably.
  • the term 'actuation element' may mean an element that is configured to emit an ultrasonic beam to actuate a corneal surface of an eye, a membrane or any deformable structure.
  • the term 'measurement element' may mean an element that is configured to emit an ultrasonic beam to facilitate measurement of a property of a corneal surface of an eye, a membrane or any deformable structure.
  • the term 'active element' may mean an element that is actuated to emit an ultrasonic beam.
  • the term 'passive element' may mean an element that is not actuated to emit an ultrasonic beam.
  • a passive element may also receive a reflected ultrasonic beam.
  • the array of elements of the ultrasonic device are passive elements. When a number of elements are activated, these elements switch to being active elements and are actuated to emit ultrasonic beams. Subsequently after emitting and transmitting the ultrasonic beams, these active elements may switch back to being passive elements.
  • the term 'active group' refers to a group of one or more elements configured to emit a plurality of ultrasonic beams while the term 'passive group' refers to a group of one or more elements configured to receive the reflected ultrasonic beam.
  • the term 'topographic profile' as applied to the corneal surface may include at least one of a curvature profile and a thickness profile of the corneal surface.
  • the term 'corneal surface' may include the surface of the cornea or the cornea itself.
  • the term 'tensional force' as applied to a corneal surface may mean a tangential force along the corneal surface, as a result of intraocular pressure.
  • the term 'corneal surface velocity' may mean a radial velocity normal to the corneal surface, as a result of acoustic actuation.
  • the corneal surface velocity is a function of geometrical coordinates and therefore may be different at different positions on the corneal surface.
  • the term 'resonant frequencies' as applied to a corneal surface may mean the frequencies at which the corneal surface or cornea vibrates at its maximum amplitude (i.e. resonance).
  • the corneal surface may experience resonance when external excitations oscillating at frequencies corresponding to the resonant frequencies of the corneal surface are applied to the corneal surface.
  • the term 'impedance' as applied to a corneal surface may mean a ratio of an acoustic pressure to a velocity along the corneal surface.
  • the acoustic pressure on the corneal surface is a function of geometrical coordinates and therefore may be different at different positions on the corneal surface.
  • one or more front-end integrated circuits may be provided in electrical communication with the array of ultrasonic transducers.
  • the word 'circuit' as applied in the term 'determination circuit' may include a circuit, a device, a component, an element, a module or the likes.
  • a 'circuit' may be understood as any kind of a logic implementing entity, which may be special purpose circuitry or a processor executing software stored in a memory, firmware, or any combination thereof.
  • a 'circuit' may be a hard-wired logic circuit or a programmable logic circuit such as a programmable processor, e.g. a microprocessor (e.g. a Complex Instruction Set Computer (CISC) processor or a Reduced Instruction Set Computer (RISC) processor).
  • a 'circuit' may also be a processor executing software, e.g. any kind of computer program, e.g. a computer program using a virtual machine code such as e.g. Java. Any other kind of implementation of the respective functions which will be described in more detail below may also be understood as a 'circuit' in accordance with an alternative embodiment.
  • any reference made to a reflected ultrasonic beam also include a reference to a plurality of reflected ultrasonic beams.
  • the term 'deformable structure' may include a membrane or a corneal surface of an eye.
  • FIG. 1 shows a schematic block diagram of a non-contact ultrasonic device 100, according to various embodiments.
  • the non-contact ultrasonic device 100 includes a plurality of first elements 102 configured to actuate a corneal surface of an eye, and a plurality of second elements 104 configured to emit a plurality of measurement ultrasonic beams on a point on the actuated corneal surface, and further configured to receive a reflected ultrasonic beam from the plurality of measurement ultrasonic beams reflected at the point on the corneal surface.
  • the plurality of first elements 102 may be configured to emit a plurality of actuation ultrasonic beams to actuate the corneal surface.
  • the plurality of second elements 104 may also be configured to actuate the corneal surface of an eye.
  • the plurality of first elements 102 may emit a plurality of actuation ultrasonic beams having a first frequency and the plurality of second elements 104 may emit a plurality of measurement ultrasonic beams having a second frequency, wherein the second frequency is higher than the first frequency.
  • Each of the plurality of first elements 102 may have a first size and each of the plurality of second elements 104 may have a second size.
  • the first size of the plurality of first elements 102 and the second size of the plurality of second elements 104 may be at least substantially same.
  • the first size of the plurality of first elements 102 and the second size of the plurality of second elements 104 may be different.
  • the first size of the plurality of first elements 102 may be larger than the second size of the plurality of second elements 104.
  • the plurality of first elements 102 may refer to larger elements emitting actuation ultrasonic beams with a low ultrasonic central frequency while the plurality of second elements 104 may refer to smaller elements emitting measurement ultrasonic beams with a high ultrasonic central frequency.
  • the plurality of second elements 104 may be arranged in a first grid pattern extending in a first direction and a second direction, wherein a number of the plurality of second elements 104 in the first direction is higher than in the second direction.
  • the plurality of first elements 102 may be arranged in a second grid pattern on a first side and a second side of the first grid pattern of the plurality of second elements 104 in the second direction.
  • the plurality of first elements 102 may be configured to actuate the corneal surface or the corneal structures dynamically.
  • the plurality of such elements may be referred to as the 'actuation elements'.
  • the plurality of second elements 104 may be configured to focus and steer the acoustic or ultrasonic beams emitted from the plurality of second elements 104 to the desired point or position on a corneal surface of an eye through an array beam-forming technology, and may be used to determine or measure corneal properties, for example the topographic profile of the corneal surface.
  • the plurality of such elements may be referred to as the 'measurement elements'.
  • the plurality of first elements 102 or the actuation elements may have a shape of a square or a rectangle.
  • the plurality of first elements 102 may have a width of between about 30 mm to about 50 mm, a length of between about 30 mm to about 50 mm and a height of about 3 mm.
  • the plurality of first elements 102 may have other sizes or shapes, for example the shape of a circle, a sphere, an oval or a polygon.
  • the plurality of first elements 102 or the actuation elements may emit ultrasonic beams with a central frequency (i.e. the first frequency) of above 100 kHz, for example in a range of between about 100 kHz to about 5 MHz (5000 kHz), for example a range of between about 100 kHz to about 3 MHz, a range of between about 100 kHz to about 1 MHz, a range of between about 100 kHz to about 500 kHz, a range of between about 500 kHz to about 5 MHz, a range of between about 500 kHz to about 3 MHz, a range of between about 500 kHz to about 1.6 MHz or a range of between about 1.6 MHz to about 5 MHz, such that the ultrasonic beams may have a central frequency of about 100 kHz, about 200 kHz, about 300 kHz, about 500 kHz, about 1 MHz, about 1.6 MHz, about 3 MHz, or about 5 MHz.
  • a central frequency i.e.
  • the plurality of second elements 104 or the measurement elements may have a shape of a square or a rectangle.
  • the plurality of second elements 104 may have a width of between about 30 mm to about 50 mm, a length of between about 30 mm to about 50 mm and a height of about 7 mm.
  • the plurality of second elements 104 may have other sizes or shapes, for example the shape of a circle, a sphere, an oval or a polygon.
  • the plurality of second elements 104 or the measurement elements may emit ultrasonic beams with a central frequency (i.e. the second frequency) of above 500 kHz, for example in a range of between about 500 kHz to about 5 MHz (5000 kHz), for example a range of between about 500 kHz to about 3 MHz, a range of between about 500 kHz to about 1 MHz, a range of between about 1 MHz to about 5 MHz, a range of between about 1.6 MHz to about 5 MHz, or a range of between about 3 MHz to about 5 MHz, such that the ultrasonic beams may have a central frequency of about 500 kHz, about 700 kHz, about 800 kHz , about 1 MHz, about 1.6 MHz, about 3 MHz or about 5 MHz.
  • a central frequency i.e. the second frequency
  • the plurality of first elements 102 and the plurality of second elements 104 form part of an array of dual-frequency air-coupled ultrasonic transducers.
  • the array of ultrasonic transducers may be configured to perform calibration of the positions of the measurement elements (i.e. the plurality of second elements 104) and the actuation elements (i.e. the plurality of first elements 102) relative to the corneal surface. The calibration process may be performed prior to measurement of the IOP.
  • the array of ultrasonic transducers as the array of ultrasonic transducers are air-coupled, the array of ultrasonic transducers utilise ambient air for the transmission of ultrasonic beams for performing measurements.
  • the measurement elements sense or measure the corneal vibration velocity (i.e. the corneal surface velocity), the corneal structural impedance (i.e. the impedance of the corneal structure) and the curvature profile of the corneal surface, as the reflected acoustic signals carry the information for these parameters and are therefore used to determine these parameters.
  • the acoustic impedance mismatch between air and cornea results in poor penetration of the ultrasonic energy or signals into the corneal surface or structure. Therefore, signals that penetrate into the corneal surface are weak and become even weaker when the signals are reflected back to the measurement elements. Such weak signals may not be sufficient for the determination of the thickness profile of the corneal surface.
  • various embodiments provide a method of determining the thickness profile based on frequency domain measurements, which overcome the issues related to the weak signals.
  • FIG. 2 shows a schematic block diagram of an ocular device 200, according to various embodiments.
  • the ocular device 200 includes a non-contact ultrasonic device 202.
  • the ocular device 200 may include a tonometer, a lens, a spectacle glass or a goggle glass.
  • FIG. 3A shows a schematic block diagram of a non-contact ultrasonic system 300 for determining an intraocular pressure of an eye, according to various embodiments.
  • the non-contact ultrasonic system 300 includes a non-contact ultrasonic device 302 and a control module 304 in electrical communication with the non-contact ultrasonic device 302, wherein the control module 304 is configured to determine the intraocular pressure.
  • FIG. 3B shows a schematic block diagram of a non-contact ultrasonic system 310 for determining an intraocular pressure of an eye, according to various embodiments.
  • the non-contact ultrasonic system 310 includes an ocular device 312 including a non-contact ultrasonic device 314 and a control module 316 in electrical communication with the non- contact ultrasonic device 314, wherein the control module 316 is configured to determine the intraocular pressure.
  • control module 304, 316 may include a digital signal processor configured to process results obtained from the non-contact ultrasonic device 302, 314.
  • control module 304, 316 is configured to perform at least one of controlling the non-contact ultrasonic device 302, 314, implementing a measurement process flow to the non-contact ultrasonic device 302, 314, implementing beam forming control to the non-contact ultrasonic device 302, 314, performing signal processing of results from the non-contact ultrasonic device 302, 314, and determining the intraocular pressure of the eye.
  • control module 304, 316 may be configured to determine a plurality of resonant frequencies of the corneal surface at a plurality of points on the corneal surface.
  • the control module 304, 316 may be further configured to determine the intraocular pressure of the eye based on the plurality of resonant frequencies.
  • the non-contact ultrasonic system 300, 310 may comprise a memory which is for example used in the processing carried out by the non-contact ultrasonic system 300, 310.
  • a memory used in the embodiments may be a volatile memory, for example a DRAM (Dynamic Random Access Memory) or a non-volatile memory, for example a PROM (Programmable Read Only Memory), an EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), or a flash memory, e.g., a floating gate memory, a charge trapping memory, an MRAM (Magnetoresistive Random Access Memory) or a PCRAM (Phase Change Random Access Memory).
  • the memory may be included in the control module 304, 316.
  • FIG. 4 shows a flow chart 400 illustrating a method of controlling a non-contact ultrasonic device, according to various embodiments.
  • actuating the corneal surface of the eye includes emitting a plurality of actuation ultrasonic beams onto the corneal surface of the eye.
  • the plurality of actuation ultrasonic beams may have a frequency of above 100 kHz, for example in a range of between about 100 kHz to about 5 MHz (5000 kHz), for example a range of between about 100 kHz to about 3 MHz, a range of between about 100 kHz to about 1 MHz, a range of between about 100 kHz to about 500 kHz, a range of between about 500 kHz to about 5 MHz, a range of between about 500 kHz to about 3 MHz, a range of between about 500 kHz to about 1.6 MHz or a range of between about 1.6 MHz to about 5 MHz, such that the plurality of actuation ultrasonic beams may have a frequency of about 100 kHz, about 200 kHz
  • a plurality of measurement ultrasonic beams are emitted on a point on the actuated corneal surface.
  • the plurality of measurement ultrasonic beams may have a frequency of above 500 kHz, for example in a range of between about 500 kHz to about 5 MHz (5000 kHz), for example a range of between about 500 kHz to about 3 MHz, a range of between about 500 kHz to about 1 MHz, a range of between about 1 MHz to about 5 MHz, a range of between about 1.6 MHz to about 5 MHz, or a range of between about 3 MHz to about 5 MHz, such that the plurality of measurement ultrasonic beams may have a frequency of about 500 kHz, about 700 kHz, about 800 kHz , about 1 MHz, about 1.6 MHz, about 3 MHz or about 5 MHz..
  • a reflected ultrasonic beam is received from the plurality of measurement ultrasonic beams reflected at the point on the corneal surface.
  • FIG. 5 shows a schematic block diagram of a non-contact ultrasonic system 500 for determining an intraocular pressure of an eye, according to various embodiments.
  • the non-contact ultrasonic system 500 includes a topographic profile determination circuit 502 configured to determine a topographic profile of a corneal surface of the eye, a tensional force determination circuit 504 configured to determine a tensional force of the corneal surface, and an intraocular pressure determination circuit 506 configured to determine the intraocular pressure of the eye based on the tensional force and the topographic profile.
  • the non-contact ultrasonic system 500 may comprise a memory which is for example used in the processing carried out by the non-contact ultrasonic system 500.
  • a memory used in the embodiments may be a volatile memory, for example a DRAM (Dynamic Random Access Memory) or a non-volatile memory, for example a PROM (Programmable Read Only Memory), an EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), or a flash memory, e.g., a floating gate memory, a charge trapping memory, an MRAM (Magnetoresistive Random Access Memory) or a PCRAM (Phase Change Random Access Memory).
  • DRAM Dynamic Random Access Memory
  • PROM Programmable Read Only Memory
  • EPROM Erasable PROM
  • EEPROM Electrical Erasable PROM
  • flash memory e.g., a floating gate memory, a charge trapping memory, an MRAM (Magnetoresistive Random Access Memory) or a PCRAM (Phase
  • FIG. 6 shows a flow chart 600 illustrating a method of determining an intraocular pressure of an eye, according to various embodiments.
  • a topographic profile of a corneal surface of the eye is determined.
  • the intraocular pressure of the eye is determined based on the tensional force and the topographic profile.
  • a plurality of first ultrasonic beams is emitted on a point on the corneal surface of the eye, and a reflected ultrasonic beam is received from the plurality of first ultrasonic beams reflected at the point on the corneal surface.
  • the plurality of first ultrasonic beams are emitted from a first active group of the plurality of first elements and the reflected ultrasonic beam from the plurality of first ultrasonic beams reflected at the point on the corneal surface is received with a first passive group of the plurality of first elements. The position of the first passive group is then determined. These processes may be repeated for a plurality of points on the corneal surface.
  • the plurality of first ultrasonic beams is emitted from a second or more active groups on the point on the corneal surface, and the reflected ultrasonic beam from the plurality of first ultrasonic beams reflected at the point on the corneal surface is received with one or more passive groups of the plurality of first elements. The positions of the one or more passive groups are then determined.
  • the reflected ultrasonic beam is transformed into a frequency domain profile so as to determine a frequency difference between at least two peaks of at least two adjacent orders of frequency components of the reflected ultrasonic beam in the frequency domain profile.
  • phase delays may be provided to at least one of the plurality of first ultrasonic beams to enable the wave fronts of the plurality of first ultrasonic beams to reach the corneal surface at least substantially simultaneously.
  • the corneal surface is actuated.
  • the corneal surface of the eye may be actuated continuously.
  • a plurality of second ultrasonic beams generating a first ultrasonic pressure, Pi, at the corneal surface is emitted from a first group of a plurality of second elements and a plurality of third ultrasonic beams generating a second ultrasonic pressure, P 2 , at the corneal surface is emitted from a second group of the plurality of second elements.
  • Pi may be at least substantially equal to P 0 8 ⁇ (2 ⁇ 0 ⁇ ) where P 0 is a peak pressure, f 0 is a frequency of the plurality of second ultrasonic beams, and t is time.
  • P 2 may be at least substantially equal to P 0 sin(2 (f 0 + 2f, )t) where P 0 is a peak pressure, (3 ⁇ 4 + 2fi) is a frequency of the plurality of third ultrasonic beams, and t is time.
  • the frequency fi may be varied.
  • a plurality of tone burst signals may be emitted at a plurality of positions on the actuated corneal surface, and a plurality of reflected tone burst signals are received from the plurality of tone burst signals reflected at the plurality of positions on the actuated corneal surface, and a frequency shift between the plurality of tone burst signals and the plurality of reflected tone burst signals at each of the plurality of positions is determined.
  • a corneal surface velocity corresponding to each of the plurality of positions on the corneal surface is determined, based on the frequency shift at each of the plurality of positions.
  • a resonant frequency of the corneal surface at each of the plurality of positions on the corneal surface is determined based on the corneal surface velocity, wherein the tensional force is a function of the corneal resonant frequency.
  • an impedance of the corneal surface is determined.
  • a reflectance of the corneal surface is determined.
  • a corneal resonant frequency is determined in order to determine the tensional force of the corneal surface at 604.
  • a corneal surface velocity is determined in order to determine the corneal resonant frequency.
  • FIG. 7 shows a schematic block diagram of a non-contact ultrasonic system 700 for determining an intraocular pressure of an eye, according to various embodiments.
  • the non-contact ultrasonic system 700 includes a topographic profile determination circuit 702 configured to determine a topographic profile of a corneal surface of the eye, a plurality of first elements 704 configured to actuate the corneal surface, a plurality of second elements 706 configured to emit a plurality of measurement ultrasonic beams on a point on the actuated corneal surface, and further configured to receive a reflected ultrasonic beam from the plurality of measurement ultrasonic beams reflected at the point on the corneal surface, and an intraocular pressure determination circuit 708 configured to determine the intraocular pressure of the eye based on the ultrasonic signal emitted, the reflected ultrasonic signal received and the topographic profile.
  • the plurality of second elements 706 may also be configured to actuate the corneal surface of an eye.
  • the non-contact ultrasonic system 700 may comprise a memory which is for example used in the processing carried out by the non-contact ultrasonic system 700.
  • a memory used in the embodiments may be a volatile memory, for example a DRAM (Dynamic Random Access Memory) or a non-volatile memory, for example a PROM (Programmable Read Only Memory), an EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), or a flash memory, e.g., a floating gate memory, a charge trapping memory, an MRAM (Magnetoresistive Random Access Memory) or a PCRAM (Phase Change Random Access Memory).
  • DRAM Dynamic Random Access Memory
  • PROM Programmable Read Only Memory
  • EPROM Erasable PROM
  • EEPROM Electrical Erasable PROM
  • flash memory e.g., a floating gate memory, a charge trapping memory, an MRAM (Magnetoresistive Random Access Memory) or a PCRAM (Phase
  • FIG. 8A shows a flow chart 800 illustrating a method of determining an intraocular pressure of an eye, according to various embodiments.
  • a topographic profile of a corneal surface of the eye is determined.
  • the corneal surface is actuated.
  • actuating the corneal surface includes emitting a plurality of actuation ultrasonic beams onto the corneal surface.
  • a plurality of measurement ultrasonic beams are emitted on a point on the actuated corneal surface.
  • a reflected ultrasonic beam is received from the plurality of measurement ultrasonic beams reflected at the point on the actuated corneal surface.
  • the intraocular pressure of the eye is determined based on the plurality of measurement ultrasonic beams emitted, the reflected ultrasonic beam received and the topographic profile.
  • FIG. 8B shows a flow chart 820 illustrating a method of determining an intraocular pressure of an eye, according to the embodiment of FIG. 8A.
  • the flow chart 820 shows the processes that may be carried out at 810 of FIG. 8A.
  • a frequency shift between the plurality of measurement ultrasonic beams and the reflected ultrasonic beam is determined.
  • a corneal surface velocity is determined based on the frequency shift.
  • a resonant frequency of the corneal surface is determined based on the corneal surface velocity.
  • a tensional force of the corneal surface is determined based on the resonant frequency.
  • FIG. 9 shows a schematic block diagram of a non-contact ultrasonic system 900 for determining an information of an eye, according to various embodiments.
  • the non- contact ultrasonic system 900 includes a plurality of elements 902 configured to emit a plurality of ultrasonic beams on a point on a corneal surface of the eye, and further configured to receive a reflected ultrasonic beam from the plurality of ultrasonic beams reflected at the point on the corneal surface, and a control module 904 in electrical communication with the plurality of elements 902, wherein the control module 904 is configured to determine a change in amplitudes between the plurality of ultrasonic beams and the reflected ultrasonic beam to determine the information.
  • the information may include an intraocular pressure or a change in an intraocular pressure.
  • the non-contact ultrasonic system 900 may comprise a memory which is for example used in the processing carried out by the non-contact ultrasonic system 900.
  • a memory used in the embodiments may be a volatile memory, for example a DRAM (Dynamic Random Access Memory) or a non-volatile memory, for example a PROM (Programmable Read Only Memory), an EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), or a flash memory, e.g., a floating gate memory, a charge trapping memory, an MRAM (Magnetoresistive Random Access Memory) or a PCRAM (Phase Change Random Access Memory).
  • the memory may be included in the control module 904.
  • FIG. 10 shows a flow chart 1000 illustrating a method of determining an information of an eye, according to various embodiments.
  • the information may include an intraocular pressure or a change in an intraocular pressure.
  • a plurality of ultrasonic beams are emitted on a point on a corneal surface of the eye.
  • a reflected ultrasonic beam is received from the plurality of ultrasonic beams reflected at the point on the corneal surface.
  • a change in amplitudes between the plurality of ultrasonic beams and the reflected ultrasonic beam is determined to determine the information.
  • the processes at 1002, 1004 and 1006, may be repeated for a plurality of points on the corneal surface of the eye.
  • FIG. 11 shows a schematic block diagram of a non-contact ultrasonic system 1 100 for determining a topographic profile of a deformable structure, according to various embodiments.
  • the non-contact ultrasonic system 1 100 includes a plurality of elements 1102 configured to emit a plurality of ultrasonic beams on a point on a surface of the deformable structure, and further configured to receive a reflected ultrasonic beam from the plurality of ultrasonic beams reflected at the point on the surface, and a control module 1104 in electrical communication with the plurality of elements 1102, wherein the control module 1 104 is configured to determine positions of the plurality of elements 1102 to determine the topographic profile.
  • the plurality of elements 1 102 includes an active group 1106 configured to emit the plurality of ultrasonic beams, and a passive group 1108 configured to receive the reflected ultrasonic beam.
  • the non-contact ultrasonic system 1100 may comprise a memory which is for example used in the processing carried out by the non-contact ultrasonic system 1 100.
  • a memory used in the embodiments may be a volatile memory, for example a DRAM (Dynamic Random Access Memory) or a non-volatile memory, for example a PROM (Programmable Read Only Memory), an EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), or a flash memory, e.g., a floating gate memory, a charge trapping memory, an MRAM (Magnetoresistive Random Access Memory) or a PCRAM (Phase Change Random Access Memory).
  • the memory may be included in the control module 1 104.
  • FIG. 12 shows a flow chart 1200 illustrating a method of determining a topographic profile of a deformable structure, according to various embodiments.
  • a plurality of ultrasonic beams are emitted from a first active group of a plurality of elements on a point on a surface of the deformable structure.
  • a reflected ultrasonic beam is received from the plurality of first ultrasonic beams reflected at the point on the surface with a first passive group of the plurality of elements.
  • positions of the first active group and the first passive group are determined to determine the topographic profile.
  • the processes at 1202, 1204 and 1206, may be repeated for a plurality of points on the surface of the deformable structure.
  • the plurality of first ultrasonic beams may be emitted from a second or more active groups on the point on the surface of the deformable structure, and the reflected ultrasonic beam may be received from the plurality of first ultrasonic beams reflected at the point on the surface with one or more passive groups of the plurality of first elements. Subsequently, positions of the plurality of first elements in the one or more passive groups may be determined. These processes may be repeated for the plurality of points on the surface of the deformable structure.
  • each of the reflected ultrasonic beams may be transformed into a frequency domain profile for determining a frequency difference between at least two peaks of at least two adjacent orders of frequency components of each of the reflected ultrasonic beam in the frequency domain profile.
  • a thickness of the deformable structure may be determined.
  • c is a phase velocity of sound in the deformable structure
  • A( is a frequency difference between the at least two peaks of the at least two adjacent orders of frequency components.
  • FIG. 13 shows a schematic block diagram of a non-contact ultrasonic device 1300 for actuating a deformable structure, according to various embodiments.
  • the non-contact ultrasonic device 1300 includes a plurality of first elements 1302 configured to emit a plurality of first ultrasonic beams having a first frequency at a surface of the deformable structure, and a plurality of second elements 1304 configured to emit a plurality of second ultrasonic beams having a second frequency at the surface of the deformable structure, wherein the second frequency comprises the first frequency and a third frequency, wherein the third frequency is lower than the first frequency, and wherein the deformable structure is effectively actuated by a half of the third frequency.
  • Each of the plurality of first elements 1302 and each of the plurality of second elements 1304 have an at least substantially similar size or dimensions.
  • the plurality of first elements 1302 may be arranged in a first grid pattern and the plurality of second elements 1304 may be arranged in a second grid pattern, and the first grid pattern and the second grid pattern are spaced apart.
  • FIG. 14 shows a flow chart 1400 illustrating a method of actuating a deformable structure, according to various embodiments.
  • a plurality of first ultrasonic beams having a first frequency is emitted for generating a first ultrasonic pressure, P ls at a surface of the deformable structure.
  • a plurality of second ultrasonic beams having a second frequency is emitted for generating a second ultrasonic pressure, P 2 , at the surface of the deformable structure, wherein the second frequency comprises the first frequency and a third frequency, wherein the third frequency is lower than the first frequency.
  • the deformable structure is effectively actuated by a half of the third frequency.
  • FIG. 15 shows a perspective view of a non-contact ultrasonic system 1500 comprising a non-contact ultrasonic device, as represented in the dotted box 1502, according to various embodiments.
  • the non-contact ultrasonic device 1502 includes an array of dual-frequency air-coupled ultrasonic transducers, including ultrasonic measurement elements 1504 and ultrasonic actuation elements.
  • the actuation elements include upper actuation elements 1506a and lower actuation elements 1506b.
  • the measurement elements 1504 may also be configured as actuation elements.
  • the measurement elements 1504 include individual elements, for example as represented by 1508 for three such elements, the upper actuation elements 1506a include individual elements, for example as represented by 1510a for two such elements, and the lower actuation elements 1506b include individual elements, for example as represented by 1510b for two such elements.
  • each individual actuation element e.g. 1510a of the upper actuation elements 1506a and each individual actuation element e.g. 1510b of the lower actuation elements 1506b, are of a larger size than each individual measurement element e.g. 1508.
  • each individual actuation element e.g. 1510a of the upper actuation elements 1506a, each individual actuation element e.g. 1510b of the lower actuation elements 1506b and each individual measurement element e.g. 1508 may have at least substantially same size.
  • the actuation elements i.e.
  • upper actuation elements 1506a and lower actuation elements 1506b emit ultrasonic beams with relatively low ultrasonic frequencies while the measurement elements 1504 emit ultrasonic beams with relatively high ultrasonic frequencies.
  • the actuation elements i.e. upper actuation elements 1506a and lower actuation elements 1506b
  • first frequency of above 100 kHz, for example in a range of between about 100 kHz to about 5 MHz (5000 kHz), for example a range of between about 100 kHz to about 3 MHz, a range of between about 100 kHz to about 1 MHz, a range of between about 100 kHz to about 500 kHz, a range of between about 500 kHz to about 5 MHz, a range of between about 500 kHz to about 3 MHz, a range of between about 500 kHz to about 1.6 MHz or a range of between about 1.6 MHz to about 5 MHz, such that the ultrasonic beams may have a central frequency of about 100 kHz, about 200 kHz, about 300 kHz, about 500 kHz, about 1 MHz, about 1.6 MHz, about 3 MHz or about 5 MHz.
  • the measurement elements 1504 may emit ultrasonic beams with a central frequency (e.g. second frequency) of above 500 kHz, for example in a range of between about 500 kHz to about 5 MHz (5000 kHz), for example a range of between about 500 kHz to about 3 MHz, a range of between about 500 kHz to about 1 MHz, a range of between about 1 MHz to about 5 MHz, a range of between about 1.6 MHz to about 5 MHz, or a range of between about 3 MHz to about 5 MHz, such that the ultrasonic beams may have a central frequency of about 500 kHz, about 700 kHz, about 800 kHz , about 1 MHz, about 1.6 MHz, about 3 MHz or about 5 MHz.
  • a central frequency e.g. second frequency
  • the measurement elements 1504 are arranged in a grid pattern extending in a first direction (e.g. an azimuthal direction 1512) and a second direction (e.g. an elevation direction 1514), wherein the measurement elements 1504 are arranged with a number of the individual measurement element e.g. 1508 of the plurality of measurement elements 1504 in the azimuthal direction 1512 higher than in the elevation direction 1514. As shown in FIG. 15, the measurement elements 1504 are arranged in a grid pattern of 16 columns and 6 rows. Therefore, the number of individual measurement element e.g. 1508 in the azimuthal direction 1512 is 16 while the number of individual measurement element e.g. 1508 in the elevation direction 1514 is 6.
  • the grid pattern may have a different number of columns and rows such that the number of individual measurement element e.g. 1508 of the measurement elements 1504 in the azimuthal direction 1512 and the elevation direction 1514 may be of a different number.
  • the number of individual measurement element e.g. 1508 in the azimuthal direction 1512 may be in a range of 10 to 30 or a range of 12 to 20 while the number of individual measurement element e.g. 1508 in the elevation direction 1514 may be in a range of 2 to 10 or a range of 4 to 8.
  • the upper actuation elements 1506a are arranged in a grid pattern extending in the azimuthal direction 1512 and the elevation direction 1514. As shown in FIG. 15, the number of individual actuation element e.g. 1510a of the upper actuation elements 1506a in the azimuthal direction 1512 is 10 while the number of individual actuation element e.g. 1510a in the elevation direction 1514 is 1. However, it should be appreciated that the number of individual actuation element e.g. 1510a of the upper actuation elements 1506a in the azimuthal direction 1512 and the elevation direction 1514 may be of a different number. For example, the number of individual actuation element e.g.
  • the description of the grid pattern of the upper actuation elements 1506a may be similarly applied to the lower actuation elements 1506b.
  • the upper actuation elements 1506a is arranged on one side of the grid pattern of the measurement elements 1504 in the elevation direction 1514 while the lower actuation elements 1506b is arranged on another side of the grid pattern of the measurement elements 1504 in the elevation direction 1514. Therefore, the upper actuation elements 1506a and the lower actuation elements 1506b are arranged on opposite sides with the measurement elements 1504 sandwiched in between, in the elevation direction 1514.
  • providing the upper actuation elements 1506a, the lower actuation elements 1506b and the measurement elements 1504 in such an arrangement or configuration may relax the alignment requirements to the corneal center, thereby improving the robustness of the measurement.
  • the number of the individual measurement element, e.g. 1508 of the plurality of measurement elements 1504, may be different in each row and/or column of the grid pattern. This similarly applies to the grid patterns of the upper actuation elements 1506a and the lower actuation elements 1506b.
  • FIG. 15 shows that the measurement elements 1504, the upper actuation elements 1506a and the lower actuation elements 1506b are arranged in grid patterns
  • the measurement elements 1504, the upper actuation elements 1506a and the lower actuation elements 1506b may be arranged in any patterns or configurations extending in a first direction (e.g. an azimuthal direction 1512) and a second direction (e.g. an elevation direction 1514), where the number of the individual element e.g. 1508 of the plurality of measurement elements 1504, 1510a of the the upper actuation elements 1506a, and 1510b of the lower actuation elements 1506b, in the azimuthal direction 1512 is higher than in the elevation direction 1514.
  • a first direction e.g. an azimuthal direction 1512
  • a second direction e.g. an elevation direction 1514
  • the non-contact ultrasonic device 1502 is bonded to a glass spectacle 1516 to form an ocular device 1518.
  • the non-contact ultrasonic device 1502 may be bonded to a glass goggle.
  • the non-contact ultrasonic device 1502 may be placed sufficiently closed to the eye 1520, at a distance of between about 1 cm to about 2 cm.
  • the non-contact ultrasonic device 1502 or the ocular device 1518 is connected to or in electrical communication with a control module 1522, via a flexible cable ribbon 1524 for providing pathways for transmission of electrical signals between the control module 1522 and the non-contact ultrasonic device 1502.
  • the cable ribbon 1524 may be in electrical communication with the non-contact ultrasonic device 1502 via a connection socket (not shown) configured to connect or couple to a front-end integrated circuit (IC) of the non-contact ultrasonic device 1502.
  • control module 1522 is configured to perform at least one of controlling the non-contact ultrasonic device 1502, implementing a measurement process flow to the non-contact ultrasonic device 1502, implementing acoustic beam forming control to the non-contact ultrasonic device 1502, performing signal processing (e.g. digital signal processing) of results from the non-contact ultrasonic device 1502 and determining the intraocular pressure of the eye 1520.
  • the control module 1522 may include a digital signal processor (not shown) configured to process the results or signals from the non-contact ultrasonic device 1502.
  • the non-contact ultrasonic system 1500 may comprise a memory which is for example used in the processing carried out by the non-contact ultrasonic system 1500.
  • a memory used in the embodiments may be a volatile memory, for example a DRAM (Dynamic Random Access Memory) or a non-volatile memory, for example a PROM (Programmable Read Only Memory), an EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), or a flash memory, e.g., a floating gate memory, a charge trapping memory, an MRAM (Magnetoresistive Random Access Memory) or a PCRAM (Phase Change Random Access Memory).
  • the memory may be included in the control module 1522.
  • the measurement of the intraocular pressure (IOP) may be achieved in a semi-continuous manner, i.e. measurements may be performed and readings of the IOP determined periodically or at a set of intervals.
  • each single IOP reading may take the steps as described below, with reference to FIGS. 15 to 17. However, it should be appreciated that one or more steps may be omitted, may be performed in addition to other steps or may be performed alternatively to other steps.
  • the non-contact ultrasonic system 1500 may perform position calibration of the non-contact ultrasonic device 1502 relative to the eye 1520.
  • the non-contact ultrasonic system 1500 may then be configured to determine a topographic profile of a corneal surface of the eye 1520, using the measurement elements 1504.
  • FIGS. 16A to 16C show cross-sectional views of a method to determine a topographic profile of a corneal surface 1600 of an eye 1520, according to various embodiments.
  • the method of determining the topographic profile of the corneal surface 1600 is first discussed with reference to the active group 1602 of the measurement elements 1504.
  • the elements in the active group 1602 are actuated electrically, they emit a plurality of ultrasonic beams 1604.
  • an element that is actuated to emit an ultrasonic beam may be referred to as an 'active element'.
  • the control module 1522 implements beam- forming control to the non- contact ultrasonic device 1502 and sets pre-determined phase delays to the elements of the active group 1602, to focus and steer the plurality of ultrasonic beams 1604 on a point 1606 on the corneal surface 1600 of the eye 1520. Therefore, the active elements of the active group 1602 emit and focus the plurality of ultrasonic beams 1604, with predetermined phase delays, on the point 1606. The incident plurality of ultrasonic beams 1604 are effectively steered and focused to the point 1606 at a certain incident angle.
  • the plurality of ultrasonic beams 1604, incident at the point 1606 of the corneal surface 1600, are reflected at the point 1606 as a reflected ultrasonic beam 1608 along a certain path at a certain reflected angle, as shown in FIG. 16A. Due to the effect of the curvature of the corneal surface 1600 at the incident point 1606, the reflected ultrasonic beam 1608 is received or detected by an element in the passive group 1610 of the measurement elements 1504. The position of the active group 1602 and position of the passive group 1610 are determined and/or recorded. In various embodiments, an element that is not actuated to emit an ultrasonic beam may be referred to as a 'passive element'. Any passive element may receive a reflected ultrasonic beam.
  • the beam- forming control steers and focuses the plurality of ultrasonic beams 1604, with pre-determined phase delays, from the active group 1602, at a different incident angle on a point 1612 on the corneal surface 1600 of the eye 1520.
  • the plurality of ultrasonic beams 1604, incident at the point 1612 are then reflected at the point 1612 as a reflected ultrasonic beam 1614 along a certain path at a certain reflected angle, different to those of the reflected ultrasonic beam 1608 (FIG. 16A).
  • the reflected ultrasonic beam 1614 is received or detected by an element in a passive group 1616 of the measurement elements 1504.
  • the position of the active group 1602 and the position of the passive group 1616 are determined and/or recorded.
  • the process of emitting and focusing the plurality of ultrasonic beams 1604 from the active group 1602, and determining the position of the active group 1602 and the position of the passive group that receives the reflected ultrasonic beam, may be repeated using the beam-forming control and steering to focus the plurality of ultrasonic beams 1604 at a plurality of points (i.e. at different points) at different incident angles on the corneal surface 1600 to scan the corneal surface 1600.
  • another active group 1618 may be actuated to emit and focus a plurality of ultrasonic beams 1620, with pre-determined phase delays, on the point 1622, at a certain incident angle, on the corneal surface 1600 of the eye 1520.
  • the plurality of ultrasonic beams 1620, incident at the point 1622 are then reflected at the point 1622 as a reflected ultrasonic beam 1624 along a certain path at a certain reflected angle, and is received or detected by an element in a passive group 1626 of the measurement elements 1504.
  • the position of the active group 1618 and the position of the passive group 1626 are determined and/or recorded.
  • the process of emitting and focusing the plurality of ultrasonic beams 1620 from the active group 1618, and determining the position of the active group 1618 and the position of the passive group that receives the reflected ultrasonic beam, may be repeated using the beam-forming control and steering to focus the plurality of ultrasonic beams 1620 at a plurality of points (i.e. at different points) at different incident angles on the corneal surface 1600 to scan the corneal surface 1600.
  • the process may be repeated using further active groups of the measurement elements 1504 to emit and focus a plurality of ultrasonic beams successively at a plurality of points on the corneal surface.
  • the process may be repeated using any active groups of the measurement elements 1504 along the azimuthal direction 1512 (FIG. 15) and/or the elevation direction 1514 (FIG. 15) on any side of the corneal surface 1600 in order to map or determine the topographic profile of the corneal surface 1600. Therefore, at any one time, an active group of the measurement elements 1504 along any column and/or row of the grid pattern of the measurement elements 1504, may be activated to emit a plurality of ultrasonic beams.
  • Further passive groups of the measurement elements 1504 may receive the ultrasonic beam reflected from the plurality of points on the corneal surface from the plurality of ultrasonic beams emitted by the further active groups of the measurement elements 1504.
  • the scanning and shifting processes of the active elements may be performed in both the azimuthal direction 1512 (FIG. 15) and the elevation direction 1514 (FIG. 15)
  • there is more freedom in the azimuthal direction 1512 (FIG. 15) due to the relatively higher number of individual element e.g. 1508 (FIG. 15) arranged in the azimuthal direction 1512 (FIG. 15) than in the elevation direction 1514 (FIG. 15).
  • the active groups 1602, 1618 include four elements. However, it should be appreciated that the active groups 1602, 1618, may include different numbers of elements actuated to emit ultrasonic beams, e.g. two elements, three elements, five elements or any number of elements.
  • the passive groups 1610, 1616, 1626 include 1 element. However, it should be appreciated that the passive groups 1610, 1616, 1626, may include different numbers of elements, e.g. two elements, three elements or any number of elements, to receive the reflected ultrasonic beam.
  • the incident angle, the reflected angle and the positions of the active group and the passive group may be determined and/or recorded.
  • the topographic profile, for example the corneal curvature profile, of the corneal surface 1600 of the eye 1520 may be determined from the incident angles, and the corresponding positions of the active groups and the positions of the passive groups determined in all the measurements performed.
  • the measurements determined may facilitate position calibrations of the array of ultrasonic transducers 1502 (FIG. 15).
  • the reflected ultrasonic beam reflected at each incident point and received by a passive group of the measurement elements may be used to determine a thickness of the corneal surface at the incident point. Accordingly, the corneal thickness profile may be determined by considering the reflected ultrasonic beams reflected at the plurality of incident points.
  • FIG. 17 shows a cross-sectional view of a method to determine a thickness at an incident point 1700 of a corneal surface 1702 of an eye, according to various embodiments.
  • a plurality of ultrasonic beams 1704 may be generated by a plurality of active elements of the measurement elements (not shown) and incident at the incident point 1700.
  • the plurality of ultrasonic beams 1704 encounter two medium interfaces or medium boundaries and three layers of transmission medium.
  • the plurality of incident ultrasonic beams are represented as a single beam 1704 in FIG. 17.
  • the plurality of ultrasonic beams 1704 may be equivalent to the plurality of ultrasonic beams 1604 (FIGS. 16A and 16B) and the plurality of ultrasonic beams 1620 (FIG. 16C) such that the process of determining the corneal curvature profile and the corneal thickness profile of the corneal surface may be performed at least substantially simultaneously.
  • the process as illustrated in FIG. 17 simultaneously occur such that the plurality of ultrasonic beams 1604 (FIG. 16A) and the plurality of ultrasonic beams 1704 (FIG. 17) refer to the same ultrasonic beams.
  • the plurality of ultrasonic beams 1704 encounter an interface 1706a between ambient air 1708 and the corneal surface 1702 and another interface 1706b between the corneal surface 1702 and the aqueous humor 1710.
  • the interfaces 1706a, 1706b form a reverberant chamber.
  • the plurality of ultrasonic beams 1704 are incident at the point 1700, a majority of the ultrasonic or acoustic energy is reflected at the interface 1706a as a 1 st - order reflected component or ultrasonic beam 1712a, while part of the ultrasonic energy is transmitted into the corneal surface 1702 as an ultrasonic beam 1714.
  • the l st -order reflected component 1712a is received by one or more passive elements of the measurement elements (not shown).
  • the ultrasonic beam 1714 is reflected and transmitted at every medium interface the ultrasonic beam 1714 encounters. As shown in FIG. 17, the ultrasonic beam 1714 is partly reflected at the interface 1706b as an ultrasonic beam 1716 towards the interface 1706a, and partly transmitted as an ultrasonic beam 1718 into the aqueous humor 1710.
  • the ultrasonic beam 1716 is then partly transmitted at the interface 1706a as a 2 nd -order component or ultrasonic beam 1712b, and partly reflected at the interface 1706a as an ultrasonic beam 1720 towards the interface 1706b.
  • the ultrasonic beam 1720 is then partly transmitted as an utrasonic beam 1722 at the interface 1706b and partly reflected at the interface 1706b as an ultrasonic beam 1724 towards the interface 1706a and subsequently partly transmitted at the interface 1706a as a 3 rd -order component or ultrasonic beam 1712c.
  • Each of the 2 nd -order component 1712b and the 3 rd -order component is received by one or more passive elements of the measurement elements (not shown).
  • the process of reflection and transmission of ultrasonic beams at the interfaces 1706a, 1706b may continue and an infinite number of components or ultrasonic beams may emerge from the interface 1706a, for example, a 4 th -order component, a S ⁇ -order component, a e ⁇ -order component and any higher order number component.
  • the different orders of components form a signal with a fixed distance in the time domain.
  • any two adjacent order of components e.g. the l st -order reflected component 1712a and the 2 nd -order reflected component 1712b, or the 2 nd -order reflected component 1712b and the 3 rd -order reflected component 1712c
  • a frequency difference or frequency shift that may be determined from the equation:
  • d is the thickness of the corneal surface 1702 at an incident point, e.g. 1700
  • c is the phase velocity of sound in the corneal surface 1702.
  • the different orders of components e.g. 1712a, 1712b, 1712c, are transformed into the frequency domain to obtain a frequency domain profile of these components.
  • the thickness profile of the corneal surface 1702 may be determined after the measurement elements (e.g. 1504 of FIGS. 15 and 16A-16C) have scanned the entire corneal surface 1702 and the thickness of the corneal surface 1702 determined at a plurality of incident points on the corneal surface 1702. Accordingly, the measurement elements (e.g. 1504 of FIGS. 15 and 16A-16C) of the array of ultrasonic transducers (e.g. 1502 of FIG.
  • each of the l st -order reflected component or reflected ultrasonic beam 1712a and its associated higher order components are transformed into a frequency domain profile so that a frequency difference between at least two peaks of at least two adjacent orders of frequency components of each of the reflected ultrasonic beam in the frequency domain profile may be determined, in order to determine the thickness of the corneal surface 1702 from equation 1.
  • various embodiments may include the topographic profile of the corneal surface when determining the intraocular pressure (IOP).
  • IOP intraocular pressure
  • the methodology of intraocular pressure (IOP) measurement may be analogous to that of a rubber balloon filled with water. As the internal pressure increases, the tensional force increases. Therefore, an increased pressure of the aqueous humor (i.e. the IOP) inside the anterior chamber of a human eye causes an increased tensional force of the corneal surface.
  • the IOP measurement is directly related to the corneal tensional force (i.e. the IOP is a function of the corneal tensional force).
  • the corneal tensional force may be determined via two independent methods, based on ultrasonic sensing schemes.
  • one method of determining the corneal tensional force is to monitor and determine the resonant frequency shift of the corneal surface or structure.
  • the corneal surface may be akin to an elastic shell filled with liquid, such that its resonant frequencies may be related to the corneal elasticity, the topographic profile (e.g. the thickness and curvature profiles) of the cornea surface and the IOP.
  • the relationship between the corneal resonance and the IOP may be determined, after having determined the topographic profile.
  • the method of determining the corneal resonant frequencies utilise acoustic actuation and sensing methods to reach accurate measurements of the resonant frequencies.
  • the term 'corneal elasticity' may mean a linearised relationship between the strain and stress of the corneal surface or structure.
  • the conventional approaches use loudspeakers to actuate the human head proximal to the corneal surface.
  • various embodiments use ultrasonic "beat" actuation technique to focus acoustic energy on the corneal surface, to achieve improved performance and measurement.
  • the actuation elements are configured to actuate the corneal surface, in order to measure the corneal resonant frequencies.
  • the actuation elements include upper actuation elements 1506a and lower actuation elements 1506b.
  • the upper actuation elements 1506a generate and emit a plurality of ultrasonic beams at an ultrasonic frequency, f 0 , thereby generating an ultrasonic pressure, Pi, at the corneal surface of the eye 1520.
  • the lower actuation elements 1506b generate and emit a plurality of ultrasonic beams at an ultrasonic frequency, (f 0 + 2fi), thereby generating an ultrasonic pressure, P 2 , at the corneal surface of the eye 1520.
  • the frequency fi is a low frequency and is lower than f 0 .
  • the ultrasonic beams emitted from elements, e.g. 1510a, in the central portion 1526a of the upper actuation elements 1506a are provided with certain pre-determined phase delays compared to the ultrasonic beams emitted by the elements, e.g. 1510a, in the outer portions 1526b, 1526c, to compensate for the planar surface of the array of ultrasonic transducers 1502 compared to the curved corneal surface of the eye 1520, so that the wave fronts of the ultrasonic beams emitted from all elements in the central portion 1526a and the outer portions 1526b, 1526c, of the upper actuation elements 1506a may reach the corneal surface at least substantially simultaneously.
  • the lower actuation elements 1506b may be configured such that the wave fronts of the ultrasonic beams emitted from all elements in the central portion 1526a and the outer portions 1526b, 1526c, of the lower actuation elements 1506b may reach the corneal surface at least substantially simultaneously.
  • the central portion 1526a may include any number of elements and correspondingly, the outer portions 1526b, 1526c may include any number of elements. Further, it should be appreciated that a different phase delay may be provided to each element, e.g. 1510a, in the central portion 1526a of the upper actuation elements 1506a and/or the lower actuation elements 1506b.
  • the ultrasonic pressure Pi generated by the plurality of ultrasonic beams at the ultrasonic frequency f 0 from the upper actuation elements 1506a, may be given by the following equation:
  • P, P 0 sin(27tf 0 t) (Equation 2), where P 0 is the peak pressure and t is the time.
  • the ultrasonic pressure P 2 generated by the plurality of ultrasonic beams at the ultrasonic frequency (f 0 + 2fi) from the lower actuation elements 1506b, may be given by the following equation:
  • P 2 P 0 sin(27i(f 0 + 2f, )t) (Equation 3), where P 0 is the peak pressure and t is the time, and where 2fi is lower than f 0 .
  • the effective pressure on the corneal surface may be determined from the following equation:
  • the corneal surface is effectively actuated by an effective pressure at the low frequency, fi with a carrier frequency (fo+fi).
  • the actuation process of the corneal surface is performed in a continuous way and may be performed independently from the measurement elements 1504.
  • there is minimal acoustic interference between the ultrasonic beams emitted from the actuation elements (e.g. the upper actuation elements 1506a and the lower actuation elements 1506b), and the measurement elements 1504 as either f 0 or 2fi is far below the operating frequency (e.g. above 500 kHz, for example in a range of between about 500 kHz to about 5 MHz (5000 kHz)) of the measurement elements 1504.
  • the frequency fi is varied through a range of frequencies.
  • the corneal resonant frequencies may be determined through the 'Doppler effect'.
  • the corneal resonant frequency at an incident point on the corneal surface may be obtained by determining the corneal surface velocity at the incident point.
  • the measurement elements may be configured to sense or determine the corneal surface velocity through the 'Doppler effect'.
  • the measurement elements 1504 may emit or send out tone burst signals (e.g. a plurality of ultrasonic beams) at a plurality of incident points on the corneal surface to scan the whole corneal surface.
  • the signals reflected at each of the plurality of incident points exhibit a frequency shift (i.e. Doppler frequency shift) from the incident signals, where the frequency shift is directly related to the corneal surface velocity at a particular incident point. Therefore, the frequency shift is a function of the corneal surface velocity at the particular incident point.
  • the corneal surface velocity at the particular incident point may be determined.
  • the corneal surface velocity V may be given by the following equation:
  • ⁇ is the Doppler frequency shift
  • c is the phase velocity of sound in the corneal surface
  • f 0 is the frequency of the plurality of ultrasonic beams generating the ultrasonic pressure Pi
  • ⁇ is the angle between the incident plurality of ultrasonic beams and the corneal surface velocity
  • the tone burst signals may be steered to a plurality of incident points on the corneal surface successively and the process of determining the corneal surface velocity is performed at each of the plurality of incident points.
  • the corneal surface velocity is determined over the whole corneal surface and accordingly, the corneal resonant frequencies may be determined over the whole corneal surface, which advantageously would be more accurate according to experimental modal analysis theory.
  • Experimental modal analysis refers to a subject that defines the methods for retrieving a structure's resonant frequencies and vibration mode shapes by observing the structure's responses.
  • a set of methods or equations may be provided to determine the corneal resonant frequencies by determining the corneal velocity.
  • the corneal tensional force may be determined.
  • An IOP reading may then be obtained, as the IOP is related to the corneal tensional force.
  • R is the corneal radius of curvature
  • E is the corneal structural elasticity
  • p is the corneal density
  • h is the corneal thickness
  • a and ⁇ are geometrical factors, a and ⁇ may be used, for example as correction factors in corneal modelling.
  • the relationship between the intraocular pressure (IOP), P, and the corneal tensional force, T may be given by the following equation:
  • T ⁇ (Equation 7), where R is the corneal radius of curvature, h is the corneal thickness and ⁇ is a geometrical factor, ⁇ may be used, for example as a correction factor in corneal modelling.
  • another method of determining the corneal tensional force is to monitor and determine the amplitudes of the ultrasonic beams reflected from the corneal surface or structure. It is known that a variation in IOP results in changes to the corneal structural tensional force. An increased IOP results in an increase in the corneal tensional force that is generated. As the corneal tensional force increases, the corneal surface becomes firmer. When ultrasonic or acoustic beams or waves are incident on the corneal surface, more acoustic energy are reflected from the corneal surface. Therefore, by monitoring the amplitudes of the reflected ultrasonic beams, the IOP may be determined.
  • This approach also allows any fluctuation in the IOP to be determined by by monitoring or analyzing any variations or changes in the amplitudes of the reflected ultrasonic beams from the corneal surface, for example monitoring the amplitudes over time to detect any variations in the amplitudes.
  • determining an absolute reading of the IOP may be challenging by using this approach solely.
  • measurements obtained by determining the variations in the amplitudes may be susceptible to noise.
  • the amplitude of an ultrasonic beam incident on the corneal surface is determined.
  • the amplitude of an ultrasonic beam reflected from the corneal surface from this incident ultrasonic beam is determined.
  • a reflectance of the corneal surface may then be determined by determining a ratio of the amplitude of the reflected ultrasonic beam to the amplitude of the incident ultrasonic beam.
  • an impedance of the corneal surface may be determined where the relationship between the impedance, z, and the reflectance, R, of the corneal surface may be given by the following equations:
  • p is the corneal density
  • c is the phase velocity of sound in the corneal surface
  • ⁇ is the incident angle of the incident ultrasonic beam.
  • the amplitude of the reflected ultrasonic beam may be determined. Any changes in the amplitude of the reflected ultrasonic beam results in a change in the reflectance, R, and hence the impedance, z, of the corneal surface. Correspondingly, the change in the impedance leads to a change in the tensional force and therefore the intraocular pressure.
  • the invention has been particularly shown and described with reference to specific embodiments, it should be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. The scope of the invention is thus indicated by the appended claims and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced.

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • Ophthalmology & Optometry (AREA)
  • Biophysics (AREA)
  • Veterinary Medicine (AREA)
  • Public Health (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • Radiology & Medical Imaging (AREA)
  • Pathology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Eye Examination Apparatus (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)

Abstract

La présente invention concerne, dans certains de ses modes de réalisation, un dispositif ultrasonique sans contact. Le dispositif ultrasonique sans contact comprend une pluralité de premiers éléments configurés pour agir sur une surface cornéenne d'un œil; et une pluralité de deuxièmes éléments configurés pour émettre une pluralité de faisceaux ultrasoniques de mesure en un point de la surface cornéenne soumise à l'action en question, et configurés en outre pour recevoir un faisceau ultrasonique réfléchi issu de la pluralité de faisceaux ultrasoniques de mesure réfléchis au point en question de la surface cornéenne.
PCT/SG2012/000112 2011-03-30 2012-03-30 Dispositif ultrasonique sans contact, système ultrasonique sans contact pour déterminer la pression intraoculaire d'un œil et procédé de détermination de la pression intraoculaire d'un œil Ceased WO2012134398A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201161469126P 2011-03-30 2011-03-30
US61/469,126 2011-03-30

Publications (1)

Publication Number Publication Date
WO2012134398A1 true WO2012134398A1 (fr) 2012-10-04

Family

ID=46931754

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SG2012/000112 Ceased WO2012134398A1 (fr) 2011-03-30 2012-03-30 Dispositif ultrasonique sans contact, système ultrasonique sans contact pour déterminer la pression intraoculaire d'un œil et procédé de détermination de la pression intraoculaire d'un œil

Country Status (1)

Country Link
WO (1) WO2012134398A1 (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111345777A (zh) * 2018-12-21 2020-06-30 中国科学院半导体研究所 基于角膜接触镜光栅的穿戴式眼压检测装置和检测方法
KR102312209B1 (ko) * 2019-11-19 2021-10-14 동국대학교 산학협력단 초음파 음향 방사력을 이용한 안압 측정 장치
WO2022005108A1 (fr) * 2020-06-30 2022-01-06 동국대학교 산학협력단 Dispositif de commande de phase pour améliorer une image d'impulsion de force de radiations acoustiques
KR20220019193A (ko) * 2020-08-07 2022-02-16 동국대학교 산학협력단 백내장 진단을 위한 초음파 검사 장치
KR20230028657A (ko) * 2021-08-20 2023-03-02 동국대학교 산학협력단 안질환 정밀 진단을 위한 초음파 변환자 및 이를 이용한 초음파 시스템
CN116077840A (zh) * 2022-09-06 2023-05-09 首都医科大学附属北京同仁医院 一种超声波角膜塑形仪
CN116211242A (zh) * 2023-02-23 2023-06-06 武汉大学 一种vr屏下眼压监测装置
KR20230148875A (ko) * 2022-04-18 2023-10-26 동국대학교 산학협력단 다중 초점 기술을 이용한 초음파 컴파운딩 영상 개선 장치
KR20240051415A (ko) * 2022-10-13 2024-04-22 동국대학교 산학협력단 위상 및 주파수 제어 기술을 이용한 초음파 컴파운딩 영상 개선 장치

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD294410A5 (de) * 1990-05-15 1991-10-02 Bezirkskrankenhaus Potsdam,De Sonographisches applanationstonometer
US5636635A (en) * 1991-10-10 1997-06-10 Massie Research Laboratories, Inc. Non-contact tonometer
US6030343A (en) * 1997-09-03 2000-02-29 Pgvc Lp Single beam tone burst ultrasonic non contact tonometer and method of measuring intraocular pressure
CA2724222A1 (fr) * 2008-05-15 2009-11-19 University Of Tsukuba Dispositif pour mesurer la frequence propre d'un tissu du globe oculaire et tonometre sans contact l'utilisant

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD294410A5 (de) * 1990-05-15 1991-10-02 Bezirkskrankenhaus Potsdam,De Sonographisches applanationstonometer
US5636635A (en) * 1991-10-10 1997-06-10 Massie Research Laboratories, Inc. Non-contact tonometer
US6030343A (en) * 1997-09-03 2000-02-29 Pgvc Lp Single beam tone burst ultrasonic non contact tonometer and method of measuring intraocular pressure
CA2724222A1 (fr) * 2008-05-15 2009-11-19 University Of Tsukuba Dispositif pour mesurer la frequence propre d'un tissu du globe oculaire et tonometre sans contact l'utilisant

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111345777A (zh) * 2018-12-21 2020-06-30 中国科学院半导体研究所 基于角膜接触镜光栅的穿戴式眼压检测装置和检测方法
KR102312209B1 (ko) * 2019-11-19 2021-10-14 동국대학교 산학협력단 초음파 음향 방사력을 이용한 안압 측정 장치
WO2022005108A1 (fr) * 2020-06-30 2022-01-06 동국대학교 산학협력단 Dispositif de commande de phase pour améliorer une image d'impulsion de force de radiations acoustiques
KR20220002767A (ko) * 2020-06-30 2022-01-07 동국대학교 산학협력단 음향방사력 임펄스 영상 개선을 위한 위상 제어 장치
KR102426027B1 (ko) * 2020-06-30 2022-07-28 동국대학교 산학협력단 음향방사력 임펄스 영상 개선을 위한 위상 제어 장치
KR20220019193A (ko) * 2020-08-07 2022-02-16 동국대학교 산학협력단 백내장 진단을 위한 초음파 검사 장치
KR102470241B1 (ko) 2020-08-07 2022-11-25 동국대학교 산학협력단 백내장 진단을 위한 초음파 검사 장치
KR102571779B1 (ko) 2021-08-20 2023-08-29 동국대학교 산학협력단 안질환 정밀 진단을 위한 초음파 변환자 및 이를 이용한 초음파 시스템
KR20230028657A (ko) * 2021-08-20 2023-03-02 동국대학교 산학협력단 안질환 정밀 진단을 위한 초음파 변환자 및 이를 이용한 초음파 시스템
KR20230148875A (ko) * 2022-04-18 2023-10-26 동국대학교 산학협력단 다중 초점 기술을 이용한 초음파 컴파운딩 영상 개선 장치
KR102735018B1 (ko) 2022-04-18 2024-11-28 동국대학교 산학협력단 다중 초점 기술을 이용한 초음파 컴파운딩 영상 개선 장치
CN116077840B (zh) * 2022-09-06 2023-10-03 首都医科大学附属北京同仁医院 一种超声波角膜塑形仪
CN116077840A (zh) * 2022-09-06 2023-05-09 首都医科大学附属北京同仁医院 一种超声波角膜塑形仪
KR20240051415A (ko) * 2022-10-13 2024-04-22 동국대학교 산학협력단 위상 및 주파수 제어 기술을 이용한 초음파 컴파운딩 영상 개선 장치
KR102792216B1 (ko) 2022-10-13 2025-04-08 동국대학교 산학협력단 위상 및 주파수 제어 기술을 이용한 초음파 컴파운딩 영상 개선 장치
CN116211242A (zh) * 2023-02-23 2023-06-06 武汉大学 一种vr屏下眼压监测装置

Similar Documents

Publication Publication Date Title
US12127977B2 (en) Ultrasonic ophthalmic device
US9462947B2 (en) Measurement method and arrangement utilizing electromagnetic waves
US6666833B1 (en) Systems and methods for focussing an acoustic energy beam transmitted through non-uniform tissue medium
US6618206B2 (en) System and method for acoustic imaging at two focal lengths with a single lens
ES2974894T3 (es) Procedimiento y dispositivo ultrasónico de caracterización de medios blandos anisótropos, y conjunto de sonda ultrasónica para dicho dispositivo de caracterización
ES2865731T3 (es) Procedimiento y disposición esquelética que utiliza ondas electromagnéticas
EP2979644B1 (fr) Sonde ultrasonore pour aiguille de ponction et dispositif de diagnostic par ultrasons l'utilisant
CN103079475B (zh) 利用凹面形态阵列的超声波图像生成方法
KR102312209B1 (ko) 초음파 음향 방사력을 이용한 안압 측정 장치
JP2010516372A (ja) 調整可能な流体レンズを使用するモーションの超音波検出方法及び装置
JP7210010B2 (ja) 水晶体硬度測定装置
US4725989A (en) Method controlling the focusing of an ultrasonic field and apparatus for performing said method
JP5397669B2 (ja) 非接触式超音波眼圧計
JP2015188467A (ja) 超音波測定装置及び測定方法
KR102470241B1 (ko) 백내장 진단을 위한 초음파 검사 장치
CN114630623B (zh) 超声换能器阵列
JP2008073391A (ja) 超音波診断装置
JP2015104498A (ja) 超音波装置
CN114209275A (zh) 一种兼容oct的光声传感器
KR102754240B1 (ko) 청각기능 개선을 위한 에어커플드 볼텍스 초음파 프로브 모듈 및 이를 이용한 초음파 영상화 시스템
US12605138B2 (en) Device and a method for monitoring an implant
Schafer et al. Design of a miniature in-vivo shock wave hydrophone
JPS62106749A (ja) 角膜厚測定用超音波プロ−ブ
JPH02261438A (ja) 角膜計測用超音波探触子
JP2024512698A (ja) 高調波特性を備えた圧電トランシーバを有するイメージングデバイス

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12763267

Country of ref document: EP

Kind code of ref document: A1

DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12763267

Country of ref document: EP

Kind code of ref document: A1