WO1993020743A1 - Reflectometre optique du domaine de coherence - Google Patents

Reflectometre optique du domaine de coherence Download PDF

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Publication number
WO1993020743A1
WO1993020743A1 PCT/US1993/003134 US9303134W WO9320743A1 WO 1993020743 A1 WO1993020743 A1 WO 1993020743A1 US 9303134 W US9303134 W US 9303134W WO 9320743 A1 WO9320743 A1 WO 9320743A1
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WO
WIPO (PCT)
Prior art keywords
signal
light path
length
light source
beamsplitter
Prior art date
Application number
PCT/US1993/003134
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English (en)
Inventor
T. Scott Rowe
Kurt D. Leukanech
Original Assignee
Alcon Surgical, Inc.
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 Alcon Surgical, Inc. filed Critical Alcon Surgical, Inc.
Publication of WO1993020743A1 publication Critical patent/WO1993020743A1/fr

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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
    • A61B3/102—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for optical coherence tomography [OCT]
    • 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
    • A61B3/1005—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for measuring distances inside the eye, e.g. thickness of the cornea
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/16—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge
    • G01B11/161—Measuring arrangements characterised by the use of optical techniques for measuring the deformation in a solid, e.g. optical strain gauge by interferometric means

Definitions

  • the present invention relates generally to optical distance measuring instruments and more specifically to instruments for measuring intraocular distances using optical coherence domain reflectometry.
  • optical coherence domain ref1ectometers optical time domain ref1ectometers
  • ultrasound scanning laser microscopes
  • scanning confocal microscopes scanning laser ophthalmoscopes
  • optical triangulation optical triangulation
  • optical time domain ref1ectometers are very expensive and have only a limited resolution and dynamic range.
  • Scanning laser or confocal microscopes and scanning laser ophthalmoscopes have excellent resolution.
  • these devices likewise are extremely expensive and the depth resolution of these devices quickly degrades as the numerical aperture is decreased, resulting in a depth resolution of only approximately 200 microns when used to measure the thickness of the retina of a human eye through the pupil.
  • Currently available optical triangulation equipment also lose depth resolution as the numerical aperture is decreased, require parallel boundaries and have a relative high signal to noise ratio.
  • the most commonly used technique, ultrasound has limited spatial resolution because of the relatively long wavelengths used and does not adequately differentiate between adjacent layers of material when the acoustic properties of each layer are similar.
  • Optical coherence domain ref1ectometers are a relatively recent innovation that solve many of the problems discussed above. These devices generally use a light source have an extremely short coherence length and an interferometer to measure phase angle changes in the light caused by the various material layers through which the light travels. For example, in their article “Absolute optical ranging using low coherence interferometry," Applied Optics. 30, pp. 2975-2979 (July 20, 1991), B.L. Danielson and C.Y. Boisrobert describe an apparatus and method for measuring short distances using an asymmetric fiber Michelson interferometer having a light emitting diode (LED) as the low coherence length light source.
  • LED light emitting diode
  • the device disclosed uses a heterodyne signal detection technique requiring a vibrating reference mirror to generate the interferograms, a mechanically complex method that increases the potential inaccuracy of the device.
  • Similar devices also are disclosed by R.C. Youngquist, S. Carr and D.E.N. Davies in their article “Optical coherence-domai reflectometry: a new optical evaluation technique," Optics Letters. 12, pp. 12-14 (March 1987) and by C.K. Hitzenberger in his article “Optical Measurement of the Axial Eye Length by Laser Doppler Interferometry," Invest. Ophth. & Visual Sciences. 32, pp. 16-19 (March 1991). Accordingly, a need continues to exist for a system capable of measuring short distances that is mechanically simple, relatively inexpensive, has a high spatial and depth resolution regardless of the numerical aperture used and is capable of distinguishing between adjacent layers of closely similar materials.
  • the present invention improves upon prior art measuring devices by providing an optical coherence domain reflecto eter using an all electronic, dual detector noise subtraction technique for measuring distances, for example, cornea! thickness, anterior chamber depth, crystalline lens thickness, axial length and retinal thickness of the human eye.
  • the system of the present invention may also be used to measure the degree of cornea motion relative to the retina, which may be useful in quantifying the ocular pulse or measuring externally forced cornea perturbations.
  • Previous art has demonstrated that the degree of cornea motion in response to acoustic excitation is related to the intraocular pressure of the eye.
  • the prior art methods propose laser doppler velocimetry and ultrasound for quantifying this motion, methods that measure cornea motion relative to the instrument itself.
  • the reflectometer of the present invention includes a low coherence length light source, a dove prism/beamsplitter, a hollow mirror retroreflector mounted on an adjustable translation stage driven by a stepper motor, a cube beamsplitter, a vertical prism and a pair of fringe pattern signal detectors.
  • Light emitted from the light source is split into two beams by the dove prism/beamsplitter, a reference beam and a measuring beam.
  • the reference beam travels through the dove prism/beamsplitter while the measuring beam is directed around the dove prism/beamsplitter through the horizontal retroref1ector mounted on the adjustable translation stage and recombines the measuring beam with the reference beam on the opposite site of the dove prism/beamsplitter.
  • the measuring beam having traveled a longer optical path through the retroreflector and around the dove prism/beamsplitter, will, in general, be out of phase with the reference beam when the two beams are recombined.
  • the amount the measuring beam is out of phase with the reference beam will depend upon the length of the alternative optical path taken by the measuring beam through the retroreflector and the coherence function of the light source.
  • the recombined beam passes through a beamsplitter cube that transmits 50% of the recombined beam and reflects the other 50% of the recombined beam into a second, fixed, vertical prism that directs this portion of the beam up and over the beamsplitter cube and into a reference detector.
  • the transmitted portion of the recombined beam is directed to the object to be measured.
  • a portion of the beam will be reflected back into the cube beamsplitter and directed into an interference photocell detector located below the reference detector by the cube beamsplitter.
  • the interference between the two beams creates an optical effect called a dynamic fringe interference pattern.
  • the detector uses optical and electronic components to convert the fringe interference pattern into an electrical fringe pattern signal that is transmitted to a noise cancellation circuit.
  • the dynamic fringe interference pattern will be contrast enhanced for each interface between layers of the test object through which the recombined beam passes.
  • the reflected, interfering beams will be brought alternately into and out of phase as the distance traveled by the horizontal retroref1ector away from the dove prism/beamsplitter equa s the optical path length created by a layer of material.
  • a root-mean-square or similar peak detection circuit converts the dynamic fringe interference pattern into a dc signal whose level fluctuates with the contrast of the dynamic fringe interference pattern.
  • the photocell detector of the present invention uses an optical band ⁇ pass filter and an all electronic noise cancellation circuit to reduce the laser and detector noise and increase the signal-to-noise ratio of the photocell detector signal.
  • This circuit is desirable because low coherence length light sources are inherently optically noisy and the intensity of the reflected, interfering measurement and reference beams reaching the photocell detector is very low. Therefore, low amounts of optical or electrical noise can result in the contrast or amplitude modulation of the interference pattern not being maximized.
  • the noise cancellation circuit operates by subtracting the scaled reference signal generated by the reference detector from the interference pattern signal, thereby eliminating laser noise and leaving only the shot noise of the detectors. Accordingly, one objective of the present invention is to provide a system for high resolution measurement using optical coherence domain reflectometry.
  • Another objective of the present invention is to provide an optical coherence domain reflectometer that uses an all electronic, dual detector noise subtraction signal detection technique.
  • Still another objective of the present invention is to provide a measuring system having a high spatial and depth resolution regardless of the numerical aperture used.
  • Still another objective of the present invention is to provide a system for measuring cornea movement relative to the retina.
  • FIG. 1 is a schematic top plan view of the present invention.
  • FIG. 2 is a schematic cross-sectional view of the present invention taken along line 2-2 in FIG. 1.
  • FIG. 3 is an illustration of a peak constructive interference signal generated by the present invention.
  • FIG. 4a is a block diagram of one suitable noise canceler circuit that may be used with the present invention.
  • FIG. 4b is a circuit diagram of one suitable noise canceler circuit that may be used with the present invention.
  • FIG. 5 is an exploded view of a material being measured taken at circle 5 in FIG. 1.
  • FIG. 6 is a block diagram of one suitable peal signal extraction computer program.
  • FIG. 7 is a graph illustrating a peak signal plotted as a function of intraocular distance.
  • the measuring system 10 of the present invention generally includes laser 12, optic 11, interferometer assembly 13 having dove prism/beamsplitter 14, horizontal retroreflector 16 having mirrors 16a and 16b, and translation stage 18, vertical prism 20, cube beamsplitter 22, reference detector assembly 24, interference detector assembly 26, computer 34 and refractive correction optics 28.
  • Laser 12 may be any laser or light emitting diode emitting radiation with a suitably short coherence length (i.e. less than approximately 100 microns ( ⁇ m)) but is preferably a multi-mode laser diode with a wavelength approximately between 700 and 1000 nanometers (nm). Suitable lasers 12 are available from sources such as Sharp, Inc.
  • CoTlimating lens 11 is preferably an asphere element and suitable lenses 11 are commercially available from Melles Griot.
  • Dove prism/beamsplitter 14 is preferably a dove prism having suitable coatings such as those available from JML Optics.
  • Refractive correction optic 28 is preferably a spectacle lens and is necessary to correct for refractive errors when system 10 is used to measure distance within the eye. Suitable optics 28 are available from sources such as Rolun Optics.
  • Cube beamsplitter 22 is preferably a 50% transmissive/50% reflective device and suitable beamsplitters 22 are available from sources such as Newport Corporation.
  • Translation stage 18 is driven by stepper motor 30, which is controlled by stepper motor controller 32.
  • Stepper motor 30 drives stage 18 through a worm gear arrangement (not shown) in 0.1 ⁇ m. linear steps, equivalent to an approximate rotation of the stepper motor shaft of 1.8°.
  • Suitable translation stages 18, stepper motors 30 and stepper motor controllers 32 are commercially available from sources such as Oriel Corporation or Minarik Electric.
  • Translation stage 18 moves retroref1ector 16 closer to or away from dove prism/beamsplitter 14 in discrete, 0.1 ⁇ m steps. The location and movement of translation stage 18 is monitored and controlled by computer 34 through controller 32.
  • detector assemblies 24 and 26 contain optical bandpass filter 36, focusing optics 38 and 40 and photocell detectors 42 and 44, respectively.
  • Filter 36 reduces the out-of-band optical noise reaching detectors 42 and 44.
  • Filter 36 is preferably a 10 nm full width at half maximum (FWHM) optical interference bandpass filter.
  • the amount of detector shot noise (NEP) is proportional to the detector surface area.
  • Lenses 38 and 40 focus reference beam 46 and interference beam.48 on detectors 42 and 44, enabling detectors 42 and 44 to have smaller surface areas and, thus, a higher signal to noise ratio.
  • Lenses 38 and 40 preferably have a focal length of 25 mm.
  • Detectors 42 and 44 convert the incident photons of beams 46 and 48 into an output signal that is directed to noise cancellation circuit 50 that electronically subtracts the signal generated by detector 42 from the signal generated by detector 44 to help eliminate any noise in beam 48 and forwards the clean signal to computer 34.
  • Detectors 42 and 44 are preferably PIN or silicon photodetectors that have their peak sensitivities at the wavelength of laser 12, and suitable detectors 42 and 44 are commercially available from sources such as EG&G Electro-Optics, Salem, Massachusetts and Silicon Detector Corporation.
  • Noise cancellation circuit 50 bases its operation on the fact that the level of photo-current noise is proportional to the D.C. level of the photo-current.
  • Reference beam 46 is a sample of the incident beam. As such, reference beam 46 does not contain any of the information of interference beam 48 but has instantaneous D.C. and noise levels directly proportional to those contained in interference beam 48. Thus, a high degree of noise cancellation can be achieved if circuit 50 can cancel any D.C. output of reference beam 46 and interference beam 48.
  • Computer 34 is preferably an IBM® compatible personal computer using at least an INTEL ® 80286 microprocessor and an INTEL® 80287 math coprocessor, but other suitable microprocessors or APPLE ® compatible computers 34 may also be used.
  • Computer 34 receives the clean signal from noise cancellation circuit 50 and controls the movement of translation stage 18 so as to locate the position of constructive interference within interference beam 48 as described more fully below and illustrated in FIG. 3.
  • an object to be measured such as eye 52
  • Lens 11 collimates beam 54 onto dove prism/beamsplitter 14 that allows part of beam 54 to be refracted by dove prism/beamsplitter 14 and while the remainder of beam 54, beam 54', is reflected around dove prism/beamsplitter 14 through retroref1ector 16 where beams 54 and 54' reco bine into interference beam 48.
  • interference beam 48 corresponding to beam 54' generally will be out of phase with the other portion of interference beam 48 corresponding to beam 54 because beam 54' must typically travel a longer optical path distance through retroref1ector 16 to reach point 56 on the other side of dove prism/beamsplitter 14 where it recombines with beam 54 to form interference beam 48.
  • the short coherence length of laser 12 causes even a slight optical path difference between beams 54 and 54' to be detectable.
  • Interference beam 48 exiting interferometer assembly 13 passes through cube beamsplitter 22 that directs a portion of beam 48, reference beam 46, into prism 22, where reference beam 46 is directed up and over beamsplitter 22 and into reference detector assembly 24.
  • the remaining portion of interference beam 48 is directed through correction elements 28 and into eye 52.
  • interference beam 48 is reflected off each surface in the anterior portion of eye 52 through which beam 48 passes.
  • the anterior surface of the cornea reflects portion 48a
  • the anterior surface of the lens reflects portion 48b
  • the posterior surface of the lens reflects portion 48c
  • the anterior surface of the retina reflects portion 48d.
  • These reflected portion of beam 48 travel back through correction elements 28 and are directed into interference detector assembly 26 by beamsplitter 22.
  • semi-transparent material 66 through which interference beam 48 first passes (such as, for example the cornea! epithelium) will generated four reflected beam 58, 60, 62 and 64 as beam 48 passes through surfaces 67 and 70.
  • Reflected beams 58 and 60 will be generated by in-phase beam 54 and reflected beams 62 and 64 will be generated by out-of-phase beam 54'. Beams 58 and 60 will not interfere constructively with each other so long as thickness 68 of material 66 is greater than the coherence length of laser 12. However, because of the adjustable optical path length of beam 54' through retroref1ector 16, beams 62 and 64 can be made to interfere constructively with beam 58. As the path length of beam 54' is shortened or lengthened by moving retroref1ector 16 closer to or farther away from dove prism/beamsplitter 14, reflected beams 62 and 64 will be pulled into and out of phase with beam 58.
  • Beam 62 will constructively interfere with beam 58 as retroref1ector 16 is pulled away from dove prism/beamsplitter 14.
  • Beam 64 will also constructively interfere with beam 58 when retroref1ector 16 is pulled away from dove prism/beamsplitter 14 an optical path difference equal to thickness 68 from the location at which beam 62 interfered with beam 58.
  • Subsequent material layers will generate similar interference patterns. For example, reflected beam 74 will interfere constructively with reflected beam 60 when retroreflector 16 is pulled away from dove prism/beamsplitter 14 an optical path difference equal to thickness 76 from the location at which beam 64 interfered with 58.
  • translation stage 18 moves retroreflector 16 toward dove prism/beamsplitter 14 until the optical path of beam 54' is exactly equal, plus or minus one wavelength, to the optical path of beam 54.
  • This will produce an interference pattern between beams 58 and 62 of maximum amplitude, and thus a peak RMS signal value, and indicates the location of top layer 67 of material 66.
  • Computer 34 directs stepper motor 30 to slowly draw retroref!ector 16 away from dove prism/beamsp ⁇ tter 14.
  • beam 64 will constructively interfere with beam 58, producing another peak output from detector assembly 26, as illustrated in FIG. 3, indicative of the bottom layer of material 66.
  • Computer 34 plots this output by location of retroref!ector 16 and the distance on the computer plot between the interference peaks caused by beams 58 and 62 and 58 and 64 is equal to thickness 68 divided by the optical index of refraction of the media being measured.
  • Computer 34 continues to slowly draw retroref!ector 16 away from dove prism/beamsplitter 14 until beam 74 constructively interferes with beam 60, indicating the location of layer 72.
  • successive layers of material will produce similar interference patterns as retroreflector 16 is continually moved away from dove prism/beamsplitter 14.
  • Computer 34 plots the location of each of these layers from which the thicknesses of the various layers can be easily calculated or seen graphically.
  • the peak signal indicative of the first layer can be isolated by a peak signal/envelope detection scheme, based on the peak of the envelope signal. The process by which the peak signal can be extracted is illustrated in the block diagram in FIG. 6.
  • the overall intent is to provide an intensity modulated output of the amplitude of the interference pattern as a function of distance.
  • Computer 34 directs stepper motor controller 32 to sweep translation stage 18 over a pre-defined range of motion. Each pulse of the digital output of computer 34 results in .1 ⁇ m of movement in translation stage 18. During this time, computer 34 continuously monitors and saves into memory the signal generated by interference beam 48 in response to the sweeping translation stage 18.
  • the interference signal information is synchronized to the motion of translation stage 18 by computer 34 creating a signal index that holds the current sample number taken for the.distance traveled. This information along with the interference signal data may be recorded on floppy or hard disk, if desired.
  • the interference signal Prior to being displayed, the interference signal is processed by computer 34 by signal conditioning, amplitude demodulation and normalization as shown in FIG. 6.
  • Signal conditioning block 84 performs low pass filtering and removed any offset or undesirable low frequency perturbations of the interference signal.
  • the conditioned signal is then amplitude demodulated to provide the envelope of the signal.
  • the demodulated signal is normalized to the first and highest peak of the interference signal. This first peak represents the first surface of the cornea and thus provides the reference point for both amplitude and distance measurements.
  • system 10 To measure cornea movement relative to the retina, system 10, once initiated, will search for the first amplitude peak (cornea reflection) and then "de-tune" from the peak to a point on the slope prior to the peak, see FIG. 7. At this point, there is extreme sensitivity to cornea to retina motion ( ⁇ d), allowing for a large amplitude deviation ( ⁇ A). With this approach, a high degree of amplitude modulation of the interference signal can take place in response to cornea to retina motion of only a few microns. Once this motion is quantified, it can be related to a particular intraocular pressure.

Abstract

L'invention se rapporte à un dispositif (10) comportant une source lumineuse laser (12) et possédant un interféromètre (13) doté d'un prisme en queue d'aronde/diviseur de faisceau (14) et d'un rétroréflecteur (16) à diviser un faisceau de lumière émise par la diode laser en un second faisceau (54) et un troisième faisceau (54'), ce dernier ayant une trajectoire lumineuse qui traverse le rétroréflecteur (16) avec une longueur variable, et à recombiner le second faisceau (54) avec le troisième faisceau (54'), un étage de transposition (18) commandé par un moteur pas à pas (30) destiné à faire varier la longueur de la trajectoire lumineuse, une lentille (28) destinée à diriger le second faisceau et le troisième faisceau (48) recombinés vers un objet (52) à mesurer de façon à ce que le second faisceau et le troisième faisceau réfléchis (48) produisent des interférences; un détecteur à cellule photoélectrique (24) destiné à convertir une configuration de frange d'interférence en un signal, un circuit d'annulation du bruit (50) destiné à soustraire le bruit de la source lumineuse du signal, et un ordinateur (34) destiné à commander le moteur pas à pas (30) et enregistrer graphiquement le signal par rapport à la longueur de la trajectoire lumineuse.
PCT/US1993/003134 1992-04-13 1993-03-31 Reflectometre optique du domaine de coherence WO1993020743A1 (fr)

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Cited By (16)

* Cited by examiner, † Cited by third party
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WO1995000068A1 (fr) * 1993-06-18 1995-01-05 Fernandes Da Cunha Vaz Jose Gu Fluorimetre oculaire
WO1999007306A3 (fr) * 1997-08-06 1999-05-14 Keravision Inc Procede et appareil de mesure des incisions de la cornee
EP0956810A1 (fr) * 1998-04-29 1999-11-17 Carl Zeiss Mesure simultanée de la longueur et de l'erreur de réfraction d'un oeil
DE19624167B4 (de) * 1995-06-23 2007-07-19 Carl Zeiss Meditec Ag Kohärenz-Biometrie und -Tomographie mit dynamischem kohärentem Fokus
US8294971B2 (en) 2008-12-18 2012-10-23 Bausch • Lomb Incorporated Apparatus comprising an optical path delay scanner
WO2012171131A1 (fr) * 2011-06-16 2012-12-20 Haute Ecole D'ingenierie Et De Gestion Du Canton De Vaud (Heig-Vd) Procede et dispositif de mesure de la pression intraoculaire
US9186059B2 (en) 2007-12-21 2015-11-17 Bausch & Lomb Incorporated Ophthalmic instrument alignment apparatus and method of using same
CN105395162A (zh) * 2015-12-21 2016-03-16 深圳市莫廷影像技术有限公司 通过电位器控制偏振控制器的方法、装置及oct系统
EP3809948A4 (fr) * 2018-06-20 2022-03-16 Acucela Inc. Système de tomographie par cohérence optique à faible coût et mobile miniaturisé pour applications ophtalmiques à domicile
US11369266B2 (en) 2020-08-04 2022-06-28 Acucela Inc. Scan pattern and signal processing for optical coherence tomography
US11393094B2 (en) 2020-09-11 2022-07-19 Acucela Inc. Artificial intelligence for evaluation of optical coherence tomography images
US11497396B2 (en) 2021-03-24 2022-11-15 Acucela Inc. Axial length measurement monitor
US11627874B2 (en) 2016-12-21 2023-04-18 Acucela Inc. Miniaturized mobile, low cost optical coherence tomography system for home based ophthalmic applications
US11730363B2 (en) 2019-12-26 2023-08-22 Acucela Inc. Optical coherence tomography patient alignment system for home based ophthalmic applications
US11911105B2 (en) 2020-09-30 2024-02-27 Acucela Inc. Myopia prediction, diagnosis, planning, and monitoring device
US11974807B2 (en) 2020-08-14 2024-05-07 Acucela Inc. System and method for optical coherence tomography a-scan decurving

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Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6013034A (en) * 1993-06-18 2000-01-11 Fernandes Da Cunha Vaz; Joseguilherme Ocular fluorometer
WO1995000068A1 (fr) * 1993-06-18 1995-01-05 Fernandes Da Cunha Vaz Jose Gu Fluorimetre oculaire
DE19624167B4 (de) * 1995-06-23 2007-07-19 Carl Zeiss Meditec Ag Kohärenz-Biometrie und -Tomographie mit dynamischem kohärentem Fokus
WO1999007306A3 (fr) * 1997-08-06 1999-05-14 Keravision Inc Procede et appareil de mesure des incisions de la cornee
EP0956810A1 (fr) * 1998-04-29 1999-11-17 Carl Zeiss Mesure simultanée de la longueur et de l'erreur de réfraction d'un oeil
US9186059B2 (en) 2007-12-21 2015-11-17 Bausch & Lomb Incorporated Ophthalmic instrument alignment apparatus and method of using same
US8294971B2 (en) 2008-12-18 2012-10-23 Bausch • Lomb Incorporated Apparatus comprising an optical path delay scanner
WO2012171131A1 (fr) * 2011-06-16 2012-12-20 Haute Ecole D'ingenierie Et De Gestion Du Canton De Vaud (Heig-Vd) Procede et dispositif de mesure de la pression intraoculaire
CN105395162A (zh) * 2015-12-21 2016-03-16 深圳市莫廷影像技术有限公司 通过电位器控制偏振控制器的方法、装置及oct系统
US11890053B2 (en) 2016-12-21 2024-02-06 Acucela Inc. Miniaturized mobile, low cost optical coherence tomography system for home based ophthalmic applications
US11627874B2 (en) 2016-12-21 2023-04-18 Acucela Inc. Miniaturized mobile, low cost optical coherence tomography system for home based ophthalmic applications
EP3809948A4 (fr) * 2018-06-20 2022-03-16 Acucela Inc. Système de tomographie par cohérence optique à faible coût et mobile miniaturisé pour applications ophtalmiques à domicile
US11357401B2 (en) 2018-06-20 2022-06-14 Acucela Inc. Miniaturized mobile, low cost optical coherence tomography system for home based ophthalmic applications
US11896308B2 (en) 2018-06-20 2024-02-13 Acucela Inc. Miniaturized mobile, low cost optical coherence tomography system for home based ophthalmic applications
US11576572B2 (en) 2018-06-20 2023-02-14 Acucela Inc. Miniaturized mobile, low cost optical coherence tomography system for home based ophthalmic applications
US11730363B2 (en) 2019-12-26 2023-08-22 Acucela Inc. Optical coherence tomography patient alignment system for home based ophthalmic applications
US11684254B2 (en) 2020-08-04 2023-06-27 Acucela Inc. Scan pattern and signal processing for optical coherence tomography
US11369266B2 (en) 2020-08-04 2022-06-28 Acucela Inc. Scan pattern and signal processing for optical coherence tomography
US11974807B2 (en) 2020-08-14 2024-05-07 Acucela Inc. System and method for optical coherence tomography a-scan decurving
US11620749B2 (en) 2020-09-11 2023-04-04 Acucela Inc. Artificial intelligence for evaluation of optical coherence tomography images
US11798164B2 (en) 2020-09-11 2023-10-24 Acucela Inc. Artificial intelligence for evaluation of optical coherence tomography images
US11393094B2 (en) 2020-09-11 2022-07-19 Acucela Inc. Artificial intelligence for evaluation of optical coherence tomography images
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