WO2011091804A1 - Appareil pour diagnostics quantitatifs de la cataracte - Google Patents

Appareil pour diagnostics quantitatifs de la cataracte Download PDF

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Publication number
WO2011091804A1
WO2011091804A1 PCT/EE2010/000003 EE2010000003W WO2011091804A1 WO 2011091804 A1 WO2011091804 A1 WO 2011091804A1 EE 2010000003 W EE2010000003 W EE 2010000003W WO 2011091804 A1 WO2011091804 A1 WO 2011091804A1
Authority
WO
WIPO (PCT)
Prior art keywords
photodetector
eye
light
eye lens
optical
Prior art date
Application number
PCT/EE2010/000003
Other languages
English (en)
Inventor
Jaak Kikas
Agu Anijalg
Koit Mauring
Original Assignee
Tartu Ülikool (University Of Tartu)
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 Tartu Ülikool (University Of Tartu) filed Critical Tartu Ülikool (University Of Tartu)
Priority to PCT/EE2010/000003 priority Critical patent/WO2011091804A1/fr
Publication of WO2011091804A1 publication Critical patent/WO2011091804A1/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
    • A61B3/117—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for examining the anterior chamber or the anterior chamber angle, e.g. gonioscopes
    • A61B3/1173—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for examining the anterior chamber or the anterior chamber angle, e.g. gonioscopes for examining the eye lens
    • A61B3/1176—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for examining the anterior chamber or the anterior chamber angle, e.g. gonioscopes for examining the eye lens for determining lens opacity, e.g. cataract
    • 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

Definitions

  • the invention refers to ophthalmology (ophthalmological diagnostic apparatus) and can be used for objective measurement of the change in the optical properties of the eye lens and also for diagnosing the extent of lenticular opacity associated with cataract development. DESCRIPTION OF THE PRIOR ART
  • the cataractous eye lens scatters light entering into the eye from pupil and diminishes the contrast as well as the sharpness of the image on the retina.
  • the stage of cataract can be quantitatively precisely evaluated by measuring the scattered light intensity.
  • the opaque eye lens scatters light inside the eye, but a certain amount of the scattered light is transmitted through the pupil back outside from the eye.
  • the knowledge of the cataract stage is important for scheduling the operation for replacing the cataractous lens with an artificial one (IOL - Intraocular Lens) .
  • a stray light meter C-Quant (Cataract Quantifier, respective patent application O2005/023103 Al) is produced by Oculus Optikgerate.
  • the psychophysical method, used to measure the intraocular stray light presupposes the evaluation by the patient of her/his subjective perceptions during the diagnostics. Therefore the apparatus can not be used for noncooperative patients. Also, the results obtained by the C-Quant have a subjective component, which diminishes their value.
  • the basic method for cataract diagnostics is examination with a slit lamp.
  • the method is subjective and rather time consuming and needs an eye specialist.
  • the prior art fails to present means for quantative objective measurement of the development of cataract with sufficient reproducibility and robustness, for reliability and consistency between different patients and the same patients in the progression of time.
  • the apparatus for quantitative cataract diagnostics disclosed herein comprises a modulated light source, photodetector, illumination optics, means for lock-in detection of the electrical current from the photodetector and a distance meter.
  • Said distance meter (which could be ultrasonic or optical) enables automatic or manual start of measurement at a fixed distance from the eye lens.
  • Ultrasonic distance meter could be equipped with means for converging the ultrasonic beam.
  • the named photodetector has a central hole, which is arranged so that the lens is illuminated with the light beam through the central hole of the said photodetector and the light, which is back-scattered from the lens, is measured by the named photodetector.
  • the shape of said photodetector shall be a ring or other design.
  • the preferred embodiment of the present invention includes the ring shaped photodetector.
  • the photodetector with a central hole can be also designed from a bundle of optical fibres, whereas the bundle terminal which collects the scattered light is having a central hole and the other terminal of the bundle of optical fibres directs the back-scattered light onto a photodetector.
  • Another object of the current invention is the apparatus whereas said photodetector has no hole and the eye lens is illuminated with the light beam, which is directed to the eye lens by the additional mirror, located in front of the photodetector.
  • the shape of said mirror shall be a ring or other design.
  • the preferred embodiment of the present invention includes the ellips-shaped mirror.
  • the apparatus can comprise optical means for visual inspection of the patient's eye during cataract quantitative diagnostics.
  • the apparatus can also comprise a position sensitive photodetector for exact positioning of the apparatus in respect of the optical axis of the eye.
  • Said position sensitive photodetector may be a quadrant photodetector.
  • the modulated or pulsed light is directed through the opening (hole) in the photodetector or after reflection by additional mirror onto an eye lens.
  • the backscattered from the lens light is detected by the photodetector and the photoelectrical signal is amplified by the lock-in amplifier which eliminates the influence of any background light.
  • the resultant voltage is converted into a digital form by the microcontroller or an analog-digital converter ADC.
  • the measurements are automatically started by the microcontroller or by an operator according to the signal from the distance meter at a specific (constant) distance from the eye.
  • Several readings are taken and the microcontroller calculates the average which quantitatively characterises the cataract and which is indicated on the display.
  • the results can be stored in the microcontroller's memory and/or can be sent to a computer connected to the apparatus by cable or over a wireless link.
  • the apparatus may comprise optical means for visual inspection of the patient's eye during diagnostics, an additional light source and a beam splitter for fixing the patient's gaze to stabilize the eye position.
  • this backscattered light is used for determination of the cataract stage.
  • the used photodetector has area extending in all directions from the optical axis of the eye, resulting in high sensitivity and uniform (in all azimuthal directions) detection of back-scattered light . This way the quantitative, numerically characterized cataract diagnostics is achieved by a portative apparatus disclosed herein.
  • Embodiments of the present invention provide an advantage over the prior art by providing an objective, quantative measurement replacement to the prevailing subjective evaluation of cataract today.
  • Fig. 1 shows the basic components of the apparatus for quantitative cataract diagnostics, comprising photodetector with a hole
  • Fig. 2 shows the basic components of the apparatus for quantitative cataract diagnostics, comprising photodetector without a hole
  • Fig. 3 depicts graphically the results of testing of the linearity of the photodetector of the current invention in comparison with the lock-in amplifier SR850 (Stanford Research Systems) .
  • the light beam 10 of the light source 1 is directed through the central hole 9 of the photodetector 3 into the eye lens 8.
  • the back-scattered light 11 from the eye lens 8 is measured by the photodetector 3.
  • the photodetector 3 In order to get good repeatability and high accuracy of the measurements, the photodetector 3 must be located at a fixed distance from the eye lens 8, which is measured by distance meter 5.
  • the microcontroller 6 detects the output signal of the distance meter 5 and when the predetermined distance is achieved, the measurement of the photodetector signal is automatically or manually (operator-controlled) started.
  • the additional light source 12 directs light onto a beam splitter 13 and further into the patient's eye.
  • the electrical current from the photodiode 3 is amplified by the lock in amplifier 4 and digitized by an ADC or the microcontroller 6 and the quantified result is displayed on a LCD-module 7.
  • the light emitting diode Hamamatsu L7868 served as the light source 1
  • the illuminaton optics 2 for collimating the light comprised a three-lens collimator GS8019 and a pinhole.
  • the photodetector was a punched photodiode VTS2080H from PerkinElmer.
  • the means for lock-in detection 4 of the photocurrent consisted of photocurrent preamplifier AD820 AC-coupled to instrumental amplifier INA118 followed by the low noise analog multiplier AD835 which functioned as a lock-in amplifier.
  • the clock generator consisted of the timer circuit NE555 followed by divider by 2 (implemented by D-trigger) which ensured the square wave duty factor of 0.5 at high precision. This was vital for perfect operation of the said lock-in amplifier, implemented on the basis of the analog multiplier.
  • the named square wave was also used for controlling the power supply of the LED.
  • the distance meter 5 was ultrasonic UNDK10U6914 from Bauraer, which ensured a distance measuring accuracy of 0.3 mm.
  • the microprocessor PIC18F4550 was used for digitalization of the analog output of the distance meter and for the automatic start of the scattered light measurement at a fixed distance from the lens. The microprocessor was also responsible for displaying the results on the LCD-module (EADIPS082 from Electronic Assembly) and for controlling the charging of the lithium-ion batteries.
  • Fig. 2 shows the apparatus where the modulated light emitted from the light source 1 is directed through the illumination optics 2 to a mirror 14, located in front of the photodetector 3.
  • the shape of said mirror shall be a ring or other design.
  • the preferred embodiment of the present invention includes the ellips-shaped mirror 14. The scattered from the patient's eye lens 8 light is detected by this photodetector 3.
  • the shape of said photodetector shall be a ring or other design.
  • the preferred embodiment of the present invention includes the ring shaped photodetector, which in combination with the ellips-shaped mirror (which has a ring-shaped shadow on the photodetector 3) form an ring-shaped active area.
  • the current from the photodiode 3 is amplified by the lock-in amplifier 4 and digitized by an ADC or the microcontroller 6 and the quantified result is ⁇ displayed on a LCD-module 7.
  • the diagnostics of the cataract is performed as follows.
  • the operator directs the light beam of the apparatus into the centre of the patient's eye pupil and after moving the apparatus in the direction to the eye, at a fixed distance from the eye, the measurement of the backscattered light is performed.
  • the result is displayed and stored in the memory of the apparatus.
  • the diagnostics is very sensitive, which allows to use very comfortable for the patient low intensity light ( ⁇ 10 ⁇ W) .
  • the measurements on the eye model showed, that the numerical results are precisely linearly dependent on the opacity and agree very well with the measurements performed with the commercial lock in amplifier.
  • the immunity of the measurements ' in respect of ambient light was tested and found that apparatus can work normally under conditions of normal lighting in the office.

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  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Medical Informatics (AREA)
  • Biophysics (AREA)
  • Ophthalmology & Optometry (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Physics & Mathematics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Eye Examination Apparatus (AREA)

Abstract

L'invention concerne un appareil portatif pour diagnostics quantitatifs de la cataracte. L'appareil comprend une source de lumière modulée, un photodétecteur, une optique d'éclairage, des moyens de détection de blocage du courant électrique provenant du photodétecteur et un appareil de mesure de distance. Le photodétecteur peut comprendre ou non un trou central et est conçu à partir d'un faisceau de fibres optiques. Le photodétecteur doté d'un trou central est placé de telle sorte que la lentille de l'œil d'un patient est éclairée par un faisceau lumineux via le trou du photo-détecteur, et la lumière rétrodiffusée est mesurée par ce dernier. Si le photo-détecteur ne comprend pas de trou, le faisceau lumineux est alors orienté vers la lentille par un miroir central situé en face du photo-détecteur. Le photodétecteur comprend une zone s'étendant dans toutes les directions à partir de l'axe optique de l'œil, ce qui a pour résultat une sensibilité élevée et une détection uniforme (dans toutes des directions azimutales) de la lumière rétrodiffusée.
PCT/EE2010/000003 2010-01-29 2010-01-29 Appareil pour diagnostics quantitatifs de la cataracte WO2011091804A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EE2010/000003 WO2011091804A1 (fr) 2010-01-29 2010-01-29 Appareil pour diagnostics quantitatifs de la cataracte

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EE2010/000003 WO2011091804A1 (fr) 2010-01-29 2010-01-29 Appareil pour diagnostics quantitatifs de la cataracte

Publications (1)

Publication Number Publication Date
WO2011091804A1 true WO2011091804A1 (fr) 2011-08-04

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014137357A1 (fr) * 2013-03-08 2014-09-12 Alethus, Inc. Détection optique sélective de substances présentes dans des tissus et des milieux troubles et utilisation à des fins d'analyse non invasive

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0231769A2 (fr) 1986-01-21 1987-08-12 Interzeag AG Appareil de mesure de l'opacité du cristallin de l'oeil humain
US5894340A (en) * 1995-02-17 1999-04-13 The Regents Of The University Of California Method for quantifying optical properties of the human lens
WO2003011122A2 (fr) * 2001-07-31 2003-02-13 The Schepens Eye Research Institute Dispositif et procedes d'imagerie servant a observer quasi-simultanement une lumiere a diffusion directe et une lumiere a diffusion multipliee
WO2005023103A1 (fr) 2003-09-05 2005-03-17 Koninklijke Nederlandse Akademie Van Wetenschappen Procede et dispositif de mesure de la lumiere parasite retinienne
US20050157261A1 (en) * 2003-12-25 2005-07-21 Nidek Co., Ltd. Eye refractive power measurement apparatus
WO2005120334A1 (fr) * 2004-06-14 2005-12-22 Eyesense Ag Appareil combine de mesure de la glycemie a partie d'un fluide oculaire
JP2006122411A (ja) * 2004-10-29 2006-05-18 Canon Inc 眼屈折力測定装置

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0231769A2 (fr) 1986-01-21 1987-08-12 Interzeag AG Appareil de mesure de l'opacité du cristallin de l'oeil humain
US5894340A (en) * 1995-02-17 1999-04-13 The Regents Of The University Of California Method for quantifying optical properties of the human lens
WO2003011122A2 (fr) * 2001-07-31 2003-02-13 The Schepens Eye Research Institute Dispositif et procedes d'imagerie servant a observer quasi-simultanement une lumiere a diffusion directe et une lumiere a diffusion multipliee
WO2005023103A1 (fr) 2003-09-05 2005-03-17 Koninklijke Nederlandse Akademie Van Wetenschappen Procede et dispositif de mesure de la lumiere parasite retinienne
US20050157261A1 (en) * 2003-12-25 2005-07-21 Nidek Co., Ltd. Eye refractive power measurement apparatus
WO2005120334A1 (fr) * 2004-06-14 2005-12-22 Eyesense Ag Appareil combine de mesure de la glycemie a partie d'un fluide oculaire
JP2006122411A (ja) * 2004-10-29 2006-05-18 Canon Inc 眼屈折力測定装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
M.P. CLARK; J.C. PEARSON; J.C.MATTHEWS: "Influence of pupil size on measurements made with the lens opacity meter 701", BRITISH JOURNAL OF OPHTHALMOLOGY, vol. 74, 1990, pages 526 - 527, XP009132242, DOI: doi:10.1136/bjo.74.9.526

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014137357A1 (fr) * 2013-03-08 2014-09-12 Alethus, Inc. Détection optique sélective de substances présentes dans des tissus et des milieux troubles et utilisation à des fins d'analyse non invasive
US10646143B2 (en) 2013-03-08 2020-05-12 Alethus, Inc. Optically discriminative detection of matters in tissues and turbid media and applications for non-invasive assay

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