WO2022200454A2 - Procédé de détermination de la pression intraoculaire - Google Patents

Procédé de détermination de la pression intraoculaire Download PDF

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Publication number
WO2022200454A2
WO2022200454A2 PCT/EP2022/057669 EP2022057669W WO2022200454A2 WO 2022200454 A2 WO2022200454 A2 WO 2022200454A2 EP 2022057669 W EP2022057669 W EP 2022057669W WO 2022200454 A2 WO2022200454 A2 WO 2022200454A2
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WO
WIPO (PCT)
Prior art keywords
eye
pulse wave
phase
ocular
pulse
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PCT/EP2022/057669
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German (de)
English (en)
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WO2022200454A3 (fr
Inventor
Rolf Meyer-Schwickerath
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Meyer Schwickerath Rolf
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Application filed by Meyer Schwickerath Rolf filed Critical Meyer Schwickerath Rolf
Publication of WO2022200454A2 publication Critical patent/WO2022200454A2/fr
Publication of WO2022200454A3 publication Critical patent/WO2022200454A3/fr

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    • 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
    • A61B3/165—Non-contacting tonometers
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
    • A61B5/14555—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases specially adapted for the eye fundus

Definitions

  • the invention relates to a method for determining the intraocular pressure according to the preamble of claim 1.
  • the invention also relates to a corresponding tonometry arrangement according to claim 7.
  • the invention also relates to a method for pulse oximetry determination of the oxygen saturation of the blood in an eye and/or or a phase of the ocular pulse wave according to claim 8 and a pulse oximetry arrangement according to claim 9.
  • tonometry is used to determine the internal pressure of the eye of a human or animal.
  • the intraocular pressure is of interest in ophthalmology, for example, insofar as an increased value represents a risk factor for glaucoma.
  • the eyeball in particular in the region of the cornea, is usually applanated in regions, ie flattened, by external influences.
  • the intraocular pressure can be determined from the force required to applanate a specific surface area of the eyeball or the cornea.
  • the deformation of the eye is usually detected optically or mechanically.
  • pressure is exerted directly on the eye using a contact lens (applanation tonometer).
  • this is uncomfortable for the person being examined and therefore requires a local anesthetic to suppress the avoidance reflex of the eye.
  • NOT non-contact tonometry
  • the eye is applanated by an air pulse.
  • a measure of the intraocular pressure can in turn be derived from the local deformation caused in this way.
  • this method is considerably less cumbersome than, for example, using a contact glass and can also be felt to be more comfortable due to the short duration and non-contact nature of the examination.
  • this advantage is accompanied by a comparatively lower level of accuracy.
  • a value for the intraocular pressure determined by the NCT is always a snapshot due to the short exposure time of the air flow.
  • a source of error results, for example, from the fact that the intraocular pressure in not is negligibly influenced by the local blood pressure in the eye and fluctuates periodically as a result of cardiac activity.
  • One approach to countering this effect can consist, for example, in carrying out a number of measurements at different time intervals over a certain period of time. An average value can then be formed from the various individual measurements and a measure of the fluctuation range can be determined.
  • An average value can then be formed from the various individual measurements and a measure of the fluctuation range can be determined.
  • the advantage of a quick and comparatively less unpleasant measurement is put into perspective again.
  • the aforementioned object is achieved by a method having the features according to claim 1 .
  • the ocular pulse wave is recorded parallel to the actual tonometry measurement, i. H. the pulse wave that arrives at the site of the eye from the heart after each heartbeat.
  • ECG electrocardiographic derivation
  • a precise moment can be selected relative to the time profile of the pulse wave arriving at the eye in order to deliver the air pulse to the eye and thus to determine the measurement time for the tonometry.
  • the synchronization of the measurement to a well-defined phase of the pulse wave is particularly important with regard to comparison measurements between different Eyes of one or more people being examined is an advantage. For example, in the context of studies in which a large number of individual measurements on different eyes or under different conditions are to be compared with one another, the increased reproducibility of the measurements as a result of the invention has a positive effect on the validity of the results.
  • any point of the pulse wave as a basis in terms of the concrete phase state, as long as this refers to the same phase state in each case.
  • the point in time when the maximum or minimum value of the pulse wave is reached is suitable for this purpose, i. H. the blood-pressure-dependent amplitude of the intraocular pressure (difference between systolic and diastolic intraocular pressure), reaching a mean value or any specified level.
  • the triggering of the air pulse of the Tonometers can also be triggered with a relevant zero crossing.
  • phase moment of the pulse wave at which the pressure inside the eye vessels and consequently the intraocular pressure experiences the strongest change in increasing and/or decreasing direction can be used, for example, as a reproducible reference time. Based on the information obtained from the course of the ocular pulse wave over time, further statements about the uniformity of successive pulse waves can also be made if necessary.
  • the phase of the ocular pulse wave is determined using the pulse oximetry method.
  • This method is basically used to determine the oxygen content of the blood.
  • tissue through which blood flows is illuminated with light of two wavelengths, usually in the red and in the infrared spectral range.
  • oxygen-rich blood differs from oxygen-poor blood by a different absorption behavior of infrared light on the one hand and light in the visible red spectrum on the other. The reason for this is the specific absorption by the hemoglobin, depending on its oxygenation. In oximetry, only the oxygen saturation of the arterial blood is usually of interest.
  • pulse oximetry uses the fact that in many cases only the diameter of the arterial vessels changes significantly with the pulse, while the usually oxygen-depleted venous blood makes a constant contribution to the determined absorption ratio due to the largely constant diameter of the venous vessels .
  • the length of the path taken by the incident light through the arterial blood also fluctuates. If a greater fluctuation in the absorption ratio is determined in the red or in the infrared range, conclusions can be drawn about the oxygen saturation of the arterial blood.
  • pulse oximetry is therefore inherent in the detection of the pulse wave on the vessel under consideration.
  • pulse oximetry is therefore suitable when used on the eye to record the ocular pulse wave and to determine its instantaneous phase and/or its course over time without significant stress for the person being tested.
  • additional information about the oxygen saturation in the eye vessels is also obtained from a pulse oximetry carried out in parallel on the eye, which can also be evaluated if required.
  • the implementation of the known pulse oximetry on the eye as a method for determining a value for the oxygen saturation of the blood in the vessels of the eye and/or for determining the ocular pulse wave, in particular the phase of the ocular pulse wave, has its own inventive aspect in connection with the present invention importance to. It has been found that in particular the tissue of the iris, the sclera, the episclera and/or the retina of an eye is suitable for the application of pulse oximetry in order to measure the local oxygen saturation in the vessels contained in the tissue and alternatively or additionally the determine local pulse wave phase.
  • a corresponding method for pulse oximetry determination of the oxygen saturation of the blood in an eye and/or a phase of the ocular pulse wave is designed according to the invention in such a way that first a tissue of the iris, the sclera, the episclera and/or the retina of the eye is illuminated by means of a light source with electromagnetic radiation of a first intensity. Furthermore, a time profile of a second intensity of the electromagnetic radiation is measured by means of a detector after at least one passage through the illuminated tissue.
  • a value for the oxygen saturation based on an amplitude of the variation and/or a value for the phase of the ocular pulse wave based on a phase of the variation is then determined from the time profile of a periodic variation in the difference between the first intensity and the second intensity.
  • a corresponding pulse oximetry arrangement within the meaning of the present invention has at least one light source and at least one detector.
  • the light source and the detector can be arranged relative to one another in such a way that electromagnetic radiation emitted by the light source can traverse a tissue of the iris, the sclera, the episclera and/or the retina of an eye at least once, preferably several times, and after exiting the tissue at least partially hits the detector and can be detected by it.
  • the pulse oximetry arrangement is preferably designed in such a way that the light source and the detector are arranged relative to one another in the application in such a way that there is an angle different from zero, preferably an angle of at least 30°, between an illumination beam path assigned to the light source and an observation beam path assigned to the detector angle of at least 45°.
  • the beam paths are clearly separated from one another and, for example, disruptive reflections of the incident electromagnetic radiation are avoided, which can falsify the measurements carried out by means of the detector.
  • the method of reflective pulse oximetry is particularly suitable for use on the eye.
  • the absorption behavior is determined by comparing incident and reflected light.
  • the use of reflected light leads to a simplification of a corresponding test arrangement, since the observed tissue of the eye does not have to be located between the light source and the detector.
  • a transmissive approach can also be pursued.
  • layers of tissue can be X-rayed in such a way that the measured second intensity corresponds to the transmitted portion of the first intensity with which the tissue was illuminated.
  • reflective pulse oximetry primarily allows localized statements on oxygen saturation, global information about the ocular blood flow in the sense of a perfusion analysis with regard to oxygen saturation can be obtained in the aforementioned manner with little effort.
  • an illumination point is preferably selected which lies behind the edge of the cornea or limbus of the eye from the frontal direction of the relevant eye.
  • the term “illumination point” refers in particular to the location from which the illumination by the light source essentially emanates.
  • the front housing edge of a light-emitting diode or the output of an optical fiber can be located there.
  • the illumination point is selected at least 1 mm, preferably at least 2 mm, particularly preferably at least 3 mm, behind the limbus of the relevant eye. This ensures undisturbed illumination or transillumination, even of deeper tissue layers.
  • the light source can be positioned on the lower lid of the eye in such a way that the electromagnetic radiation it emits first crosses the lower lid before it reaches the eyeball and the tissue layers of the eye to be illuminated or transilluminated.
  • the electromagnetic radiation is usually scattered in such a way that the front tissue layers are illuminated or transilluminated from the rear space. After the radiation has passed through the tissue layer of surprisingly, it can be measured in the form of a second intensity by a corresponding detector, in particular in a time-resolved manner.
  • a suitable detector can also be positioned on the lower lid of the eye in such a way that an intensity of the reflected and/or transmitted electromagnetic radiation is measured after it has passed through the skin and other tissue layers of the lower lid.
  • a space-saving apparatus structure can thus be implemented for carrying out the method according to the invention.
  • the light source is preferably positioned on the inner side of the eye and/or the detector on the temporal side of the eye. This preferably results in a structure for carrying out the method which is symmetrical with respect to the eye.
  • a measurement through further, possibly scattering tissue layers is particularly possible since no imaging information is required according to the method, but only an intensity value, preferably over time, is used to detect the ocular pulse wave or to determine the oxygen saturation. For this reason, a comparatively compact and simply constructed sensor, for example a photodiode or the like, can also be used. An expensive image sensor in the sense of a camera sensor, CCD chip or the like is therefore preferably dispensed with in the context of the method according to the invention.
  • the phase of the ocular pulse wave is particularly preferably determined on a vessel of the iris, the sclera and/or the episclera of the eye.
  • viewing the aforementioned front tissue layers of the eye or the vessels contained therein has the advantage that the pupil and the area of the cornea in front of it do not have to be kept free in order to keep the retina accessible, for example optically.
  • a maximum value, a minimum value and intermediate reference levels can be determined or defined in this way.
  • the ocular pulse wave is particularly preferably recorded over several full periods over time. This allows random deviations from an average pulse waveform to be identified and quantified. In particular, this results in the possibility of randomly and/or periodically occurring phase fluctuations, i. H. so-called jitter errors, to be detected, quantified and taken into account when evaluating the measurement results.
  • averaging the recorded pulse wave is the possibility of analyzing the shape of the pulse wave over time with regard to reproducible peculiarities that are not compensated for by the averaging process. On the basis of such a consideration, outstanding phase times can be determined, which are suitable for a closer examination or a targeted synchronization of the NCT measurement.
  • the current phase of the ocular pulse wave is known, it is possible, as described, to establish a specific, well-defined phase point at which the tonometric measurement, ie in particular the triggering of the air pulse, is to take place.
  • points in the time course of the pulse wave are preferably selected at which a clear effect of the vascular pressure on the intraocular pressure is to be expected.
  • the moment in which the passing ocular pulse wave reaches its maximum and/or minimum amplitude value appears to be particularly suitable in this regard. If the tonometry is carried out at this moment, an upper or lower limit for the intraocular pressure can be determined. If the NCT is carried out both at the maximum point and at the minimum point, a fluctuation range for the intraocular pressure can be determined.
  • an illumination beam path for incident electromagnetic radiation in particular red and/or infrared light
  • an observation beam path for corresponding electromagnetic radiation reflected on the illuminated tissue layers different angles to a reference surface, for example the observed tissue layer to arrange.
  • An angle greater than zero between the two beam paths avoids interference effects due to reflections at additional boundary surfaces between the radiation source or the detector and the tissue being observed.
  • the exact angle between the beam paths depends on the application situation, in particular with regard to the angle relative to the additional boundary layers mentioned.
  • an angle between the illumination beam path and the observation beam path of at least 30°, preferably at least 45°, has a particularly advantageous effect.
  • a tonometry arrangement for determining the intraocular pressure which allows a method of the type described above to be carried out, also has its own inventive significance.
  • a device initially comprises a non-contact tonometer, which is designed to be controlled or triggered by an external trigger impulse.
  • the tonometry arrangement according to the invention comprises an arrangement, coupled to the tonometer, for detecting the ocular pulse wave with regard to its phase or its progression over time.
  • the arrangement for detecting the ocular pulse wave is preferably an arrangement for, in particular, reflective pulse oximetry on the eye.
  • Commercially available pulse oximeters are often designed for transmissive pulse oximetry by x-raying tissue layers of the skin on the extremities, for example fingertips or earlobes.
  • Reflectively functioning sensors such as those used in smart watches, are common also designed for use on skin tissue.
  • a corresponding arrangement for, in particular, reflective pulse oximetry on the eye must be suitable for reliably detecting the pulse wave, but at the same time enabling a tonometric measurement.
  • the corresponding arrangement for detecting the ocular pulse wave is preferably designed to detect the pulse wave using vessels of the iris, the sclera and/or the episclera of the eye, in particular by means of reflective pulse oximetry.
  • the tonometry arrangement preferably also includes a control device, for example in the form of an electronic circuit and/or a data processing device, in order to couple the determined phase of the ocular pulse wave and the implementation of the tonometry measurement or the triggering of the air pulse with one another, i. H. synchronize the tonometry to the phase of the ocular pulse wave.
  • the coupling can take place in a simple manner by simply forwarding a trigger pulse to the tonometer when a specific phase value of the pulse wave is reached. Such a trigger pulse can, if required, be emitted or forwarded after a delay time that can be selected in particular.
  • any known time shifts between the corresponding phases of the ocular pulse wave and the intraocular pressure that follows it can be taken into account. Furthermore, in this way it is possible to avoid or compensate for measurement artefacts if they occur, for example, as a result of a vibration of the eye induced by a strong air pulse of the applanation method. As an alternative or in addition, an accompanying and/or prior evaluation of the course over time or the shape of the ocular pulse wave can also take place, in particular by means of statistical methods.
  • control device and/or a possibly separate data processing device can also be used to evaluate measurement results from the tonometer.
  • FIG. 1 shows a schematic representation of a tonometry arrangement for carrying out the method according to the invention
  • FIG. 2 shows a schematic sectional representation of part of the arrangement from FIG.
  • FIG. 3 shows a schematic representation of an arrangement for carrying out a preferred embodiment of the method according to the invention.
  • FIG. 4 shows a comparative, schematic representation of the course over time of the ocular pulse wave.
  • the tonometry arrangement 1 shows a preferred embodiment of a tonometry arrangement 1 according to the invention, by means of which non-contact tonometry, i.e. a non-contact determination of the intraocular pressure, can be carried out on an eye 2.
  • the tonometry arrangement 1 comprises a tonometer 3 in the form of a non-contact tonometer and an arrangement for determining the phase of the ocular pulse wave 5, the course of which over time is shown schematically in FIG. 4 by way of example.
  • the arrangement for determining the phase of the ocular pulse wave is a pulse oximetry arrangement 4.
  • the tonometer 3 has an outlet nozzle 6, by means of which an air pulse in the form of a brief gas stream can be emitted in the direction of the eye 2.
  • the eyeball 7 of the eye 2 is briefly applanated, i.e. deformed by local flattening, particularly in the area of the fibrous skin 8 .
  • a value for the intraocular pressure can be determined, which counteracts the deformation.
  • the deformation of the eyeball 7 is recorded in a basically known manner by means of a corresponding device, in particular optically. For reasons of clarity of the illustration, such a device of the tonometer 3 is not shown in detail here.
  • the delivery of the air pulse through the outlet nozzle 6 of the tonometer 3 and the associated measurement of the deformation of the eyeball 7 or the cornea 8 is, according to the invention, synchronized with a specific phase of the ocular pulse wave 5 chronicled.
  • the ocular pulse wave 5 is preferably detected by the method of, in particular, reflective pulse oximetry.
  • a corresponding arrangement is shown schematically in FIG.
  • Electromagnetic radiation is emitted from a light source 9 onto tissue of the eye 2 .
  • the reflected light is then received by a detector 10 .
  • An illumination beam path 11 of the incident light and an observation beam path 12, through which the detector 10 receives part of the reflected radiation, are preferably spatially separated from one another by a certain angle W, as shown in particular in FIG.
  • the angle W contributes to a better separation of the incident light from the reflected radiation and thus to a more reliable measurement.
  • the angle W between the illumination beam path 11 and the observation beam path 12 is preferably at least 30°, preferably at least 45°.
  • the light source 9 generates light of at least two wavelengths, in particular one wavelength in the visible red spectrum and one wavelength in the infrared spectrum. Examples of suitable wavelengths are approx. 650 nm for the red range and approx. 900 nm for the infrared range.
  • the light source 9 can have a corresponding number of individual emission sources, for example in the form of LEDs, which are not shown in detail in the figures.
  • the emission sources can be designed to be controllable separately from one another.
  • the detector 10 which, if required, can also have a corresponding number of sensors.
  • each wavelength used is assigned its own illumination beam path 11 and/or its own observation beam path 12 .
  • the incident light strikes the iris 13 through the cornea 8 and illuminates the vessels 14 therein in the form of arteries and veins, which are not shown separately from one another.
  • absorption takes place more strongly in the visible red or in the infrared spectral range.
  • the intensity of the light of the corresponding wavelength is reduced to a greater or lesser extent.
  • the light is reflected irregularly at the iris background 15 and, if necessary, traverses the vessels 14 again, as a result of which the attenuation effect is further intensified. A part of the reflected light is now detected by the detector 10 via the observation beam path 12 .
  • the light source 9 can also be positioned in such a way that the electromagnetic radiation it emits enters the eyeball 7 at least essentially away from the tissue layers of the eye 2 to be illuminated, is scattered isotropically in the latter and then comes from the rear direction on the viewing direction of the eye 2, passes through the relevant tissue layers before it is detected by the detector 10.
  • a corresponding arrangement for this is shown in FIG. 3 by way of example.
  • the scattering of the electromagnetic radiation, which enters the eyeball 7 according to the illumination beam path 11, is indicated there by arrows.
  • the illumination beam path 11 and/or the observation beam path 12 run in particular through the lower eyelid of the eye 2, which is not shown in detail.
  • the light source 9 is preferably arranged on the inner side of the eye 2 .
  • the detector 10 can be arranged on the temporal side of the eye 2, preferably in a symmetrical position with respect to the light source 9.
  • an illumination point from which the light source 9 at least essentially emits the electromagnetic radiation is on the side of the plane defined by the outer edge of the cornea 8a that faces the eyeball 7, which is generally essentially in the region of the iris 13 and extends parallel to this.
  • the illumination point is preferably at least 1 mm, preferably at least 2 mm, particularly preferably at least 3 mm, behind this plane, based on the front view of the eye 2, or in front of this plane, based on the viewing direction of the eye 2.
  • the arterial vessels 14 periodically pulsate with the ocular pulse wave 5.
  • the change in diameter associated with the pulsation has a direct effect on the extinction according to the Lambert-Beer law.
  • the diameter of the veins filled with relatively low-oxygen blood preferably remains largely constant.
  • a periodic fluctuation in the intensity ratio of the reflected light in the red and in the infrared range is thus detected with the detector 10 . Due to the direct dependence of the extinction on the arterial vessel diameter, which in turn depends on the current, local vessel pressure, the phase of the ocular pulse wave 5 can be determined using the detector signal, and can preferably even be read directly from it.
  • the tonometry arrangement 1 preferably comprises a control device 16 which can send a control command to the tonometer 3 as a function of the signal from the detector 10 .
  • the control command is in particular a trigger pulse that activates the tonometer 3 to carry out a tonometric measurement. This usually involves the delivery of a pulse of air through the outlet nozzle 6.
  • control device 16 is designed to be more complex, for example as a data processing device, and allows further processing of the detector signal. This includes in particular the storage and a preferably statistical evaluation of the detector data which reflect the ocular pulse wave 5 . A statistical evaluation is possible, in particular, based on a recording of several full period passages of the ocular pulse wave 5 .
  • the method according to the invention can also detect the ocular pulse wave 5 on a vessel 14 of the sclera and/or the episclera of the eye 2.
  • the method it is also possible to use the method on the conjunctiva. Both alternatives have the advantage, like the detection at the iris 13, that, for example, the pupil 17 and the cornea 8 in front of it are not blocked and parallel measurements, such as tonometry in the present case, can be carried out in this area with little design effort .
  • FIG. 4 shows the course of the ocular pulse wave 5 over time in comparison with the parallel course over time of a schematic electrocardiogram 18, which reproduces the electrical activities of the heart excitation and could be recorded by a corresponding ECG derivation. That simplifies
  • the electrocardiogram 18 shown is shown in graph a) in FIG. 4 at the top.
  • graph b) the ocular pulse wave 5 is shown in the sense of a pressure change in the eye due to the passage of the pulse wave generated by the heart.
  • Graph c) also shows the time profile of the intensity 19 of the reflected light as it is recorded in principle by the detector 10 or by the control device 16 in conjunction with the detector 10 when using the pulse oximetry method becomes.
  • a schematic profile of the relevant values in arbitrary units (“arbitrary units" [au]) is shown in each case, plotted against time t. The time axis is the same for all three graphs a), b) and c) shown.
  • the maximum of the ocular pulse wave 5 lags behind the heartbeat or the classically derivable ECG signal by a certain period of time.
  • the peak value to be measured by a corresponding ECG derivation which essentially coincides in time with the pulse activity of the heart, occurs in the example shown at a pulse point in time T p .
  • T p a pulse point in time
  • the time lag between T p and T max is fundamentally dependent on the individual case and cannot be determined without a comparatively complex investigation.
  • the phase of the ocular pressure wave 5 behaves essentially synchronously with the measurable intensity fluctuation in the pulse oximetry performed on the eye.
  • the intensity 19 measured by the detector 10 can basically be divided into a constant base component DC and a variable oscillation component AC.
  • the constancy of the base component DC is due on the one hand to the contribution of the venous vessels, the diameter of which hardly changes with the heartbeat, and on the other hand to the contribution of the arterial vessels 14 with a minimum diameter, which is present in the diastolic case.
  • the layer thickness-dependent extinction therefore does not change.
  • the maximum fluctuation amplitude represents the oscillation component AC.
  • a change in the intensity ratio of the reflected light of the different wavelengths due to the periodically fluctuating contribution of the arterial blood to the total extinction is used in pulse oximetry as a measure of the oxygen saturation.
  • the time component of the recorded data is of particular interest.
  • various distinguished points in time can be determined on the basis of the phase of the ocular pulse wave 5 . These include, for example, the maximum point in time T max , i.e.
  • one or more reference levels R can be defined, the crossing of which is in ascending and/or descending order Direction characterized in each case a specific phase time To.
  • a reference level R defined between the maximum and minimum value of the ocular pulse wave 5 or the detected intensity 19 can represent a specific mean value of the vessel pressure in the sense of a zero point, upon which a tonometric measurement is triggered at the phase point in time To.
  • the statistical evaluation of several runs of the ocular pulse wave 5 based on the recording over several period lengths P allows a more reliable determination of the relevant points in time To, Tmax, Tmin of the phase of the ocular pulse wave 5 ocular pulse wave 5, of interest.
  • a drift in the pulse frequency and/or pulse amplitude can be determined from the consideration of a plurality of consecutive period lengths P, which also has effects to the points in time To, T max , T min of reaching a specific phase of the ocular pulse wave 5 .

Abstract

L'invention concerne un procédé de détermination de la pression intraoculaire par tonométrie sans contact. Selon l'invention, la mesure tonométrique est synchronisée avec une phase déterminée de l'onde pulsée oculaire.
PCT/EP2022/057669 2021-03-23 2022-03-23 Procédé de détermination de la pression intraoculaire WO2022200454A2 (fr)

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JP3927898B2 (ja) * 2002-10-25 2007-06-13 キヤノン株式会社 非接触式眼圧計
WO2008058386A1 (fr) * 2006-11-16 2008-05-22 Rsem, Limited Partnership Appareil et procédé pour mesurer un déplacement dans un œil in vivo in situ, et procédé d'évaluation
EP3119268B1 (fr) * 2014-03-07 2024-05-01 Lions Eye Institute Limited Procédé et système pour déterminer la pression intracrânienne

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