EP1545293A1 - Dispositif et procede d'adaptation de lentilles de contact a un oeil - Google Patents

Dispositif et procede d'adaptation de lentilles de contact a un oeil

Info

Publication number
EP1545293A1
EP1545293A1 EP03793703A EP03793703A EP1545293A1 EP 1545293 A1 EP1545293 A1 EP 1545293A1 EP 03793703 A EP03793703 A EP 03793703A EP 03793703 A EP03793703 A EP 03793703A EP 1545293 A1 EP1545293 A1 EP 1545293A1
Authority
EP
European Patent Office
Prior art keywords
contact lens
eye
determined
measurement
light source
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.)
Withdrawn
Application number
EP03793703A
Other languages
German (de)
English (en)
Inventor
Kristian Hohla
Birte Jansen
Gerhard Youssefi
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.)
Individual
Original Assignee
Individual
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
Priority claimed from DE2002141210 external-priority patent/DE10241210B4/de
Priority claimed from DE2003116576 external-priority patent/DE10316576B3/de
Application filed by Individual filed Critical Individual
Publication of EP1545293A1 publication Critical patent/EP1545293A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
    • G02C7/00—Optical parts
    • G02C7/02—Lenses; Lens systems ; Methods of designing lenses
    • G02C7/021—Lenses; Lens systems ; Methods of designing lenses with pattern for identification or with cosmetic or therapeutic effects
    • 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
    • G—PHYSICS
    • G02—OPTICS
    • G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
    • G02C7/00—Optical parts
    • G02C7/02—Lenses; Lens systems ; Methods of designing lenses
    • G02C7/04—Contact lenses for the eyes

Definitions

  • the present invention relates to an apparatus and method for fitting contact lenses to an eye.
  • spherical contact lenses are adapted to a patient to correct ametropia, then usually only the degree of ametropia to be corrected is taken into account, i. the strength of myopia or hyperopia.
  • the contact lens is not directly on the optical axis of the eye, ie centrically in front of the pupil of the patient, it produces a prismatic aberration. This aberration is traditionally accepted, as it only leads to a slight impairment of the quality of vision.
  • the translational deviation of the contact lens center point from the pupil center and thus also from the optical axis of the eye is referred to as decentration.
  • the disadvantage of such decentration becomes particularly great when adapting refractive multifocal contact lenses, i. Contact lenses with areas of different focal lengths. In the adaptation of such contact lenses so far a contact lens must be determined by trial and error, which is as centrally as possible in front of the pupil of the patient.
  • a toric or cylindrical contact lens is adapted. It has a so-called cylinder axis which corresponds to the direction of its minimum or maximum refractive power. This cylinder axis extends from the contact lens center point in the radial direction. To be able to correct a corneal astigmatism, the cylindrical axis position of the contact lens on the eye must be stable. Toric contact lenses sen therefore a directional stabilization. It takes place z. B. by incorporating a prism in the contact lens, which complains the lower, optically unused area of the contact lens. Due to gravity, the contact lens in the eye rotates until the support rim, weighted by the prism, comes to rest inferior.
  • Another known method of directional stabilization is the inferior and superiore flattening of the support rim of the contact lens. Through the blink of the eye, the lens rotates on the eye until the flattened areas come to rest under the upper and lower eyelid.
  • a directionally stabilized contact lens should be stable in its axial position after about half an hour wearing time. After this wearing time, the contact lens is viewed on a slit lamp in the patient's eye. The axial position can then be determined either directly in a measuring eyepiece on the slit lamp, or by rotating the slit lamp in the position indicated by the marking and subsequent measurement of the slit lamp rotation.
  • a so-called tabo scheme is used for measuring the axis position. The 0 ° axis of the tabo scheme lies horizontally at three o'clock. From there, the angles are calculated counterclockwise.
  • the axis of the contact lens runs vertically downwards from the contact lens center point, this corresponds to an axial position of 270 ° in the tabular diagram. It may happen that the measurement of the axis position is impossible because the contact lens continues to rotate too much. In this case, a more stable seated lens must be found by trial and error.
  • a device for position measurement of contact lenses on the eye is known from US 5,686,981. By means of the device described there above all the decentration of the contact lens on the eye is to be determined. However, the measurements made are not very meaningful and also uncomfortable for the patient.
  • An object of the present invention is to improve known methods of fitting contact lenses to an eye so that the method becomes more reliable.
  • a second object is to provide a device by means of which the fitting method can be carried out.
  • the first object is achieved by a method having the features of claim 1.
  • the second object is achieved by a device having the features of claim 37.
  • the method according to the invention is mainly due to the fact that the position of the contact lens on the eye at a plurality of measuring times is taken into account.
  • the measured position data can include the decentration of the contact lens and / or direction-stabilized contact lenses whose axial position.
  • the method according to the invention becomes more meaningful in that a value resulting from the position of the contact lens is not found by trial and error, but is calculated. Such a value allows a comparison of the location data between different patients and / or contact lens types.
  • the method according to the invention makes it possible to adapt the patient to a more suitable contact lens. On the basis of the calculated value, it is possible, for example, to select the type of contact lens which has the lowest decentration on the patient's eye. Even with spherical contact lenses so the disadvantage of a light prism because of a decentering of the contact lens no longer be tolerated.
  • the calculated value is the calculated value with regard to the production of customized or patient-specific contact lenses. If the stable position of a contact lens is detected on an eye, it can be carried out based on the values calculated from the position data, a post-processing of this lens or a blank blank same that the post-processing or processing the position of the contact lens with respect to the optical axis of the eye and / or a corneal astigmatism considered.
  • a particularly meaningful value is obtained if an average value is calculated from the position data over a plurality of measurement times.
  • An alternative possibility is to create a frequency distribution of the measured values and to calculate the maximum of this frequency distribution. This avoids strongly deviating measured values.
  • the location of the contact lens center may be determined. This is preferably done by determining the location of the contact lens center on the basis of the edge of the contact lens and / or at least one peripheral marking on the contact lens. Thus, it is not necessary to mark the contact lens center itself by a possibly obstructive mark.
  • the decentrations of the contact lens in the horizontal and / or vertical direction relative to the reference point are determined.
  • a particularly good reference point on the eye is the pupil center because it passes through the optical axis of the eye.
  • Both lens selection and lens processing are preferably performed with respect to the optical axis of the eye.
  • the coordinates of the center of the contact lens with respect to the coordinates of the pupil center can be measured.
  • the pupil center can be determined, for example, by deducing the pupil center on the basis of the edge of the pupil.
  • An alternative to using the pupillary center as a reference point on the eye is to apply an artificial reference point at a defined location on the eye before decentring measurement. This may be, for example, a color marking or a local indentation of the cornea.
  • a mark could be applied to the contact lens having a preferential direction (e.g., parallel) defined to the axis. As soon as this preferred direction is detected, the axis position of the contact lens is determined at the same time.
  • a mark could, for example, be an arrow or a cross whose one arm is extended.
  • Another possibility would be to determine the coordinates of at least two markings attached to the contact lens, whose position relative to one another and to the cylinder axis is known. From the coordinates, the axis position of the contact lens can then be calculated. The method according to the invention can be carried out considerably faster if the decentring data and the axis position data are determined at the same measuring times.
  • the adaptation method according to the invention is particularly elegant in that a photographic image is taken at each measurement time and the positional data of the contact lens is determined from the image. This is the first step towards automation and speeding up the process.
  • a difficulty may be that the position of a transparent body is to be determined with the contact lens.
  • the contrast of the exposure can be increased by a suitable choice of lighting.
  • a lighting with a light source which has at least a strong infrared component or even an exclusive IR light source.
  • the patient does not feel dazzled, so the measurements are more pleasant for him.
  • his pupil widens and, as explained later, allows a particularly meaningful wavefront measurement on the eye contact lens system.
  • a plurality of photographic images are taken at a measuring instant in rapid succession (for example at intervals of a few hundred microseconds or 1-2 ms) in which the light is incident at different angles.
  • a mark on the outside of the contact lens will cast a shadow on the eye surface, which is different depending on the angle of incidence of the light.
  • the exact position of the marking on the contact lens is determined from the migration of the shadow of the marking. This is particularly easy to do when the mark extends to the edge of the contact lens. Since the edge of the contact lens rests directly on the eye, the shadow of the mark does not migrate at this point. From the comparison of several recordings can be so it is very easy to detect the location where the mark cuts the edge of the contact lens.
  • the image field of the images is so large that it covers the entire contact lens. This increases the accuracy of the measured position data and the values calculated therefrom.
  • the images are created with a digital camera.
  • the existing in digital form recordings can be particularly well processed and stored, for example.
  • digital recordings allow each to subtract two images with different illumination in a computer from each other to further increase the contrast of the thus calculated recording. It has been shown that certain contact lens materials have a transmission minimum in the blue spectral range. The surroundings of the contact lens can therefore be darkened mathematically by subtracting a picture taken with monochromatic light at the transmission minimum from a picture taken with another illumination.
  • the images can be spectrally decomposed, i. in their blue, red and green parts when using a color camera. A colored marking is then particularly well visible in a spectral component.
  • a particularly great advantage of digital recordings is that the position data of the contact lens can be determined by a computer program.
  • a pattern-recognizing program can be used for this purpose, which recognizes the markings on the contact lens and / or calculates the respective center from the edge of the contact lens or pupil.
  • the exposure time per exposure is at most 25 milliseconds (ms) since the movement of the contact lens during this time can be neglected. It is particularly useful to create the recordings with a repetition rate of at least 5 Hz. Between two pairs of eyelids it is thus possible to create a large number of recordings on which the contact lens is at least partially visible and thus make it possible to determine the position data.
  • those images are preferably sorted out on which the pupil is at least partially covered by the eyelid.
  • the determination of the center of the pupil is not or only inaccurately possible on these images.
  • the rest position of the contact lens can be determined, for example, by subtracting the position data from each of two successive measuring times and determining the minimum of the differences thus formed in order to determine the positional convergence. In this way, regardless of the movement of the lid those measurements are determined between which the contact lens has moved or rotated only slightly. For this purpose, it is expedient if in each case a constant time difference exists between two measuring times.
  • Another important statement can be obtained by specifying the standard used for the calculation of the value from the position data of the contact lens. dard deviation is determined. The size of the standard deviations allows a statement about the accuracy with which the contact lens complies with the calculated position. In this way, contact lenses can be selected, which remain particularly reliable in a particular position.
  • the measurement at this measurement time can thus be selected as an exemplary measurement.
  • a wavefront measurement is carried out at one or more measuring times using a contact lens which is seated on the eye.
  • the data obtained from this can be taken into account together with the values determined from the position data in the production of a customer-specific contact lens.
  • the measurement of wavefronts at a plurality of different measurement times also offers the possibility of calculating from the measurements an average of the wavefront, which can subsequently be used as a basis for post-processing the contact lens or a contact lens blank.
  • a laser engraving may be provided on it, which extends on the optical zone of the contact lens, so with the contact lens attached over the pupil of the user.
  • the laser engraving can be produced either by ablating through a diaphragm or by passing a very small laser focus over a scanner to directly generate the engraving. Any shapes are conceivable for the engraving. For example, they may be formed as intersecting or intersecting dotted lines. These lines can be NEN meet eg in the form of a Y, a cross or a star in the optical center of the contact lens. If the engraving is rotationally asymmetrical, it can be deduced from its orientation to the axial position of the contact lens.
  • the wavefront measurement for example, with a helium-neon laser at low intensity is irradiated into the eye.
  • the laser light is reflected by the retina of the eye.
  • the laser light is scattered at the engraving.
  • the engravings are dark in front of the very bright pupil visible through the reflected laser light.
  • the strong contrast between the bright pupil and the dark engravings makes it possible to evaluate the image by means of a computer and to determine the coordinates of the engravings.
  • the decentering and the axial position of the contact lens relative to the center of the pupil can be calculated.
  • a refractive measurement is performed on the eye contact lens system.
  • a refractive measurement is performed on the eye contact lens system.
  • the wavefront of the optical system of eye and contact lens blank is measured.
  • mittein it is possible to mittein over a plurality of measuring points.
  • a great advantage of the position measurement just described by means of the coordinates of preferably punctiform engravings is that the wavefront of the eye contact lens system can be measured through the engraving.
  • the wavefront measurement is based on a punctiform light source on the retina. This light can originate, for example, from the irradiated HeNe laser.
  • the small engravings on the surface of the contact lens blank do not disturb the wavefront measurement, especially as the wavefront measurement does not focus on the surface of the contact lens blank. The position measurement and the wavefront measurement can thus be carried out simultaneously.
  • a device which can be used to carry out the method according to the invention.
  • a device can be used, for example, in an eye clinic or at an ophthalmologist or optician for the adaptation of contact lenses. It comprises at least one measuring unit for position measurement of a contact lens and a computer for calculating a value from the position data.
  • the device itself has a camera with which the images are taken, for example a digital camera.
  • the device itself may comprise at least one directional light source, which may be directed toward the patient's eye for amplifying the illumination.
  • the position and / or the orientation of at least one light source are adjustable, so that such a position and / or orientation of the light source can be selected, in which the contrast of the recording is as high as possible.
  • At least one polarization filter and / or color filter is provided in front of the light source.
  • the device has an attachment unit for the head of a patient.
  • This investment unit may include, for example, a chin rest and a forehead support, or lateral contact elements. It serves to bring the head of the patient and in particular his eyes to the device and its camera in a stable position. In this way, the image sections between different shots match very well.
  • the exposure time and / or the repetition rate of the images taken with the camera are adjustable on the device. They can thus be adapted to the circumstances prevailing during the measurement, for example the intensity of the illumination, and to the behavior of the contact lens on the eye in order to obtain as meaningful measurements as possible.
  • the device itself preferably has a computer unit which serves for determining the position data from the recordings and for calculating the values to be obtained from the position data.
  • a wavefront analysis device can be provided in the device with which wavefront measurements can be carried out on the patient's eye with or without a seated contact lens.
  • the wavefront analysis device can be synchronized with the camera via a common clock, so that the position data are obtained simultaneously with the wavefront measurement.
  • FIG. 1 shows a front view of a patient's eye with an attached contact lens
  • FIG. 2 a schematic representation of the contact lens and the pupil of the eye
  • FIG. 3 shows a frequency distribution of a measured value in the X direction obtained in the method according to the invention
  • Figure 4 is a schematic representation of an apparatus for performing the method according to the invention for fitting contact lenses to an eye.
  • FIG. 1 shows an eye 1 of a patient on which a contact lens 2 is placed.
  • the following parts are shown by the eye itself: the pupil 3, the iris 4, the upper lid 5 and the lower lid 6.
  • the fitted contact lens 2 is usually a hydrated, soft contact lens.
  • the method according to the invention can also be used for hard contact lenses.
  • the inserted contact lens 2 is directionally stabilized and has a radial preferred direction, its so-called axis 7.
  • the position of the axis 7 is marked on the contact lens 2 by markings 8. These may, for example, be engravings on the contact lens surface.
  • markings 8 may, for example, be engravings on the contact lens surface.
  • the four outer ones exist in a line pointing to the contact lens center.
  • the middle mark 8 is emphasized by a dash, so that it has the shape of a cross. Through this middle mark 8, the axis 7 of the contact lens 2 runs.
  • Directional stability can be generated in a contact lens 2, for example, by the fact that its optically effective zone 9 (see FIG. 2) has an elliptical shape in plan view and adjoins this optical zone 9 with support edges 10 flattened on two sides. Due to the impact of the upper lid 5, the support edges 10 of the contact lens 2 are directed substantially downwards or upwards.
  • a spherical contact lens 2 in which the optical zone 9 has the same refractive power in each direction there is a preferential direction of the contact lens in the connecting line through the mark 8 and the contact lens center. This preferred direction defines the axis 7 of the contact lens 2.
  • FIG. 1 The view shown in FIG. 1 is part of a photograph 11 that can be made in the method according to the invention. It is bounded by its edge 12. In a corner of the receptacle 11, an XY coordinate system 13 is shown. Its X and Y axes are located on the edges 12 of the receptacle 11. They are selected so that the X-axis in the horizontal direction and the Y-axis in the vertical direction.
  • FIG. 2 shows a contact lens 2 which has an elliptical optical zone 9 and flattened carrier edges 10 for directional stabilization.
  • the circumference of the support edges 10 and thus of the contact lens 2 is circular and defines the contact lens center 15 as the center of this circle.
  • the axis 7 of the contact lens 2 extends radially from the contact lens center 15 to the mark 8 on the lower support edge 10, which identifies the axial position of the contact lens 2.
  • the marking 8, for example an engraving on the contact lens surface, here has the shape of a cross with an extended arm 16.
  • the mark 8 is located exactly on the axis 7. Due to the extended arm 16, the mark 8 has a preferred direction, with the axis of the 7th coincides and points to the contact lens center 15.
  • the contact lens center 15 has the coordinates (X c , Y c ). They can be determined by passing a circle through three arbitrary points A, B and C on the edge of the contact lens and determining the coordinates of the center of this circle.
  • FIG. 2 also shows the circular pupil 3 of the eye 1.
  • the pupil center 17 lies in the coordinate system 13 (see FIG. 1) at the coordinates (X p , Y P ). These coordinates can be determined in an analogous manner to those of the contact lens center point 15 by passing through three points E, F and G on the edge of the pupil 3, a circle is passed through and the coordinates of the circle center are determined.
  • the pupil center 17 extends the optical axis of the eye 1.
  • the contact lens 2 is decentered from the pupil 3, i. the centers 15, 17 of the contact lens 2 and the pupil 3 do not match.
  • the decentration in the X or Y direction results as
  • FIG. 3 shows a diagram of a frequency distribution of the measured values for decentring ⁇ X in the X direction obtained in the method according to the invention.
  • This diagram shows the measured decentrations ⁇ X. They are summarized in equidistant intervals I.
  • each interval I may correspond to a range of 0.1 mm.
  • the ordinate indicates the frequency P with which a value .DELTA.X occurred in a certain interval I from a plurality of measurements.
  • the midpoint of the interval I in which most of the measured values lie is denoted by X 0 . It indicates the maximum of the frequency distribution shown in FIG.
  • FIG. 4 shows a diagram of a device 20 which can be used for the method according to the invention for fitting contact lenses 2 to an eye 1.
  • an attachment unit 21 is provided on the device 20. It may for example comprise a chin rest and / or a forehead support and serves to bring the head of the patient and in particular his eye 1 opposite the device 20 in a stable position.
  • a camera 22 can be oriented so that its image field captures the eye 1 of the patient.
  • a digital camera is used as the camera 22, which is controlled and read out via a central processing unit 23 of the device 20.
  • the arithmetic unit 23 comprises not only a computer 24 but also a memory 25 and a clock generator 26.
  • a monitor 27 is connected to the arithmetic unit 23.
  • a directional light source 28 is provided, the position and / or orientation of which is adjustable via an adjustment unit 29.
  • the light emitted by the light source 28 is filtered by a filter unit 30.
  • the filter unit 30 may comprise, for example, color filters and / or polarization filters. Dashed lines indicate that the light source 28, its setting unit 29 and the filter unit 30 can be actuated by the central processing unit 23 of the device 20.
  • the illuminance can be set, the position and / or orientation of the light source 28 can be specified or computer-controlled various filters can be exchanged for one another.
  • the light source 28 is an IR light source or has at least a strong infrared component, since it widens the pupil of the eye 1, without the patient feeling dazzled.
  • the device 20 also has a wavefront analysis unit 31. It is used to measure the wavefront of the eye 1 with or without seated contact lens 2. As wavefront analysis unit 31, for example, a Hartmann-Shack sensor can be used.
  • the wavefront analysis unit 31 can also be controlled and read by the arithmetic unit 23 in the exemplary embodiment shown.
  • the clock 26 of the arithmetic unit 23, which predetermines the measurement times, enables a synchronization of the camera 22, the wavefront analysis unit 31 and possibly also the light source 28.
  • the device 20 further comprises two beam splitters 32, by means of which the optical axes of the camera 22, the wavefront analysis unit 31 and the light source 28 can be aligned coaxially with each other.
  • the light paths 33 can be adjusted so that they capture the eye 1 of the patient.
  • a processing station 34 for contact lenses 2 or contact lens blanks, which produces patient-specific contact lenses 2 and takes into account the values calculated in the method according to the invention, may be located outside the device 20. Preferably, however, it is integrated into the device 20.
  • a set of fitting lenses is available whose lenses 2 are all directionally stabilized and have spherical values at intervals of one or two diopters (dpt).
  • the fitting lens set may include a plurality of different lenses of the same thickness, e.g. with different inner radii or diameters. Furthermore, it can also contain toric lenses.
  • a contact lens 2 is selected, which corrects the patient as well as possible.
  • the contact lens 2 is placed on the eye 1 of the patient. If it is a soft contact lens, it must first be hydrated. After an entry time of about half an hour, the contact lens 2 has taken a stable position on the eye 1.
  • the patient puts his head on the attachment unit 21. For example, his chin lies on a chin rest and his forehead on a forehead rest. His eye 1 thus has a defined position relative to the device 20.
  • the operator of the device for example an ophthalmologist, an optician or an assistant, adjusts the camera 22, the light source 28 and the wavefront analysis unit 31 so that they respectively the patient's eye 1 to capture.
  • This adjustment can be facilitated by the fact that the image of the camera 22 is continuously output to the monitor 27.
  • the operator can also control whether the image is sharp and the contrast sufficient to detect the edges of the contact lens 2 and the pupil 3 and the markers 8 on the contact lens 2. If this is not the case, the position or orientation of the light source 28 can be changed or another filter can be selected in the filter unit 30 by means of the setting unit 29. If the contrast is sufficient, a filter can also be dispensed with.
  • the clock 26 of the arithmetic unit 23 provides a plurality of measurement times.
  • the frequency and the number of these measuring times are adjustable by the operator. For example, 50 measurements can be made at a repetition rate of 10 Hz so that the total duration of the measurements is 5 seconds.
  • the camera 22 creates a digital image 11 of the patient's eye 1.
  • the wavefront analysis unit 31 performs a measurement of the wavefront of the patient's eye 1 with the contact lens 2 seated on it.
  • the digital images 11 and the results of the wavefront measurement are transferred to the arithmetic unit 23 and stored on the memory 25.
  • the wavefront can be represented by a Zernike polynomial, it suffices to represent the wavefront, to store the pupil diameter and the coefficients of the individual terms of the Zemike polynomial. These are the so-called Zemike amplitudes.
  • the images 11 taken From the images 11 taken, those images are sorted out on which the pupil 3 is at least partially covered by the eyelid 5, since these images do not allow a reliable determination of the position data.
  • a computer program is provided which determines whether the entire pupil 3 is visible on a receptacle 11.
  • the pupil 3 is significantly darker than the surrounding iris 4 and can therefore easily be found by a picture-recognizing computer program.
  • the images 11 taken with the camera 22 are black / white images, in order to save storage space and to increase the computing speed.
  • the position data of the contact lens 2 at each measurement time are also determined by means of a computer program. Depending on the computational effort, this can either be done immediately after creating each individual shot 11 or after the end of a large number of measurements.
  • the coordinates (X c , Y c ) of the contact lens center 15 and (X p , Y p ) of the pupil center 17 are determined.
  • a circle is adapted to the edge of the contact lens 2 and to the edge of the pupil 3, and the position of the center of the circle is determined.
  • the adjustment of the circle can be done either by an operator who draws on the monitor 27 a circle in the desired size and location, or by means of a computer program that detects the coordinates of at least three points on the respective edge and a circle of appropriate size by this passes three points. From the measured coordinates which are related to the coordinate system 13 of the receptacle 11 (cf., FIG. 1), the horizontal and vertical decentrations ⁇ X, ⁇ Y of the contact lens 2 with respect to the pupil center 17 are calculated.
  • the axial position 7 of the contact lens 2 can be determined in different ways. Each path can be performed by both an operator and a computer program that recognizes images. If the marking 8 on the contact lens 2 has a certain preferred direction, such as, for example, the extended arm 16 of the cross in FIG. 2, then only this preferred direction must be recognized. Since it lies on the axis 7 of the contact lens 2, both have the same orientation in the coordinate system 13.
  • a second possibility for determining the axial position 7 is to determine the coordinates of a marking 8 located above the axis 7 and of the contact lens center point 15.
  • the connecting line through these two points corresponds to the axis 7 of the contact lens 2.
  • are two or more markers 8 are attached to the contact lens 2, the positions of which are known on the contact lens 2, there is a third way to measure the axial position 7 in the determination of the coordinates of at least two of the markers 8. From these coordinates can then on the Position of the axis 7 can be closed back.
  • both the data of the (translational) decentration and (rotational) axis position of the contact lens 2 can be determined in this way.
  • the Achslage 7 is usually shown in the so-called Tabo scheme.
  • the contact lens 2 assumes an axial position of about 300 °.
  • a value can now be calculated.
  • the value is calculated separately for the horizontal decentering ⁇ X, the vertical decentration ⁇ Y and the axis position.
  • the mean value over all measured values can be formed as a meaningful value. It indicates in which position the contact lens 2 was located on average during the entire measuring time. It can be assumed that the contact lens 2 will occupy this position most frequently on the eye 1 of the patient.
  • Another, equally meaningful value is the maximum of a frequency distribution of the measured values.
  • the measured values as shown in FIG. 3, are divided into intervals I and a frequency distribution is formed.
  • the maximum X 0 of this frequency distribution indicates which position the contact lens 2 has most frequently taken on the eye 1.
  • This method does not take into account measured values where the position data deviate from the maximum of the frequency distribution. This may be advantageous above all with regard to the measurement of the vertical decentration ⁇ X. Due to the eyelid impact, the movement of the contact lens 2 on the eye 1 in the vertical direction is strongest.
  • the maximum of the frequency distribution of the measured values will approximately correspond to the rest position occupied by the contact lens 2 between two eye flashes.
  • this rest position can be determined even more precisely by subtracting the position data from two adjacent measurement times from one another and the Minimum of these differences is determined.
  • the assumption of the rest position of the contact lens 2 is equivalent to the fact that their position data change only slightly from one measurement time to the next.
  • the mean values are calculated in each case for the horizontal decentration and the axis position, while the maximum of the frequency distribution of the measured values is calculated for the vertical decentration ⁇ Y because of the stronger movement of the contact lens 2 in this direction.
  • the values calculated in this way can be used in various ways.
  • One possibility is to measure a plurality of different contact lenses 2 on the patient's eye 1. Subsequently, that contact lens 2 can be selected which has the lowest decentration in the horizontal and / or vertical direction. Such a selection was previously possible only by trial and error. The lower the decentration, the lower the prism induced during vision.
  • the selection of a suitable contact lens can be further improved by calculating the size of the standard deviation from the position data and then selecting the contact lens 2 in which the standard deviation has a minimum. This indicates that this contact lens remains particularly reliably in a certain position, instead of wandering around in the eye. A contact lens selection from this point of view was previously impossible.
  • a conventional presbyopia-correcting contact lens 2 is successful only if its optical zone is centered with respect to the pupil center 17. If the decentering and / or the axial position of the contact lens 2 are calculated by means of the present method, these values can be incorporated into the patient-specific adaptation and processing of a contact lens 2. In particular, the optical zone 9 of the contact lens 2 can be corrected so that it is aligned exactly in front of the pupil center 17. In addition, the near and far regions of a multifocal contact lens 2 can be worked in such a way that they have a specific orientation on the eye 1 in the preferred, central axis position 7. Both conventional (ring) structures of multifocal lenses, as well as new structures such as a coma can due to The measured data are incorporated so that they are centered towards the center of the contact lens or the middle of the pupil.
  • the position data can be considered, but also the measured wavefront of the patient's eye 1 with seated contact lens 2. If the wavefront has been measured at several times, then an average value can be calculated from the measured wavefronts, which then the Post-processing of the contact lens or a blank is used as a basis. Alternatively, the measured wavefront could be taken into account in the post-processing, at the time of measurement of which the position of the attached contact lens corresponded particularly well to the value calculated from the position data. For this, the minimum of the deviation of the measured position data would have to be determined from the values calculated therefrom.
  • the patient-specific post-processing of a contact lens 2 can be done either on the contact lens measured on the eye, or on a manufacture-identical contact lens blank. For hard contact lens materials, both variants can be used. For soft materials, the treatment is preferably carried out on a blank prior to its hydration. An appropriate source factor must be taken into account.
  • the method described above and the device 20 used therefor can be modified in many ways.
  • a topography analysis unit that measures the topography of the corneal surface of the eye 1.
  • These data could also be incorporated into a post-processing of a patient-specific contact lens.
  • an artificial reference point on the eye 1. The position of the contact lens 2 could then be measured with respect to this artificial reference point. This could be a small color point or a notch introduced by a laser shot.

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Abstract

L'invention concerne un procédé d'adaptation de lentilles de contact à un oeil, ainsi que le dispositif servant à la mise en oeuvre d'un tel procédé. De manière avantageuse, le procédé selon l'invention permet de déterminer la position d'une lentille de contact sur un oeil à plusieurs instants de mesure, et de calculer au moins une valeur à partir des données de position, servant par la suite de base pour le choix ou le traitement des lentilles.
EP03793703A 2002-09-05 2003-08-07 Dispositif et procede d'adaptation de lentilles de contact a un oeil Withdrawn EP1545293A1 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
DE2002141210 DE10241210B4 (de) 2002-09-05 2002-09-05 Vorrichtung und Verfahren zum Anpassen von Kontaktlinsen an ein Auge
DE10241210 2002-09-05
DE10316576 2003-04-10
DE2003116576 DE10316576B3 (de) 2003-04-10 2003-04-10 Verfahren und Vorrichtung zum Herstellen weicher Kontaktlinsen
PCT/EP2003/008787 WO2004021875A1 (fr) 2002-09-05 2003-08-07 Dispositif et procede d'adaptation de lentilles de contact a un oeil

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Publication Number Publication Date
EP1545293A1 true EP1545293A1 (fr) 2005-06-29

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EP03793703A Withdrawn EP1545293A1 (fr) 2002-09-05 2003-08-07 Dispositif et procede d'adaptation de lentilles de contact a un oeil

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EP (1) EP1545293A1 (fr)
AU (1) AU2003253394A1 (fr)
WO (1) WO2004021875A1 (fr)

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Publication number Priority date Publication date Assignee Title
US7216978B2 (en) * 2005-06-08 2007-05-15 Johnson & Johnson Vision Care, Inc. Method for evaluating eyelid movement and contact lens position
US8777413B2 (en) 2006-01-20 2014-07-15 Clarity Medical Systems, Inc. Ophthalmic wavefront sensor operating in parallel sampling and lock-in detection mode
US8820929B2 (en) * 2006-01-20 2014-09-02 Clarity Medical Systems, Inc. Real-time measurement/display/record/playback of wavefront data for use in vision correction procedures
US8100530B2 (en) 2006-01-20 2012-01-24 Clarity Medical Systems, Inc. Optimizing vision correction procedures
US9113819B2 (en) 2006-01-20 2015-08-25 Clarity Medical Systems, Inc. Apparatus and method for operating a real time large diopter range sequential wavefront sensor
US9101292B2 (en) 2006-01-20 2015-08-11 Clarity Medical Systems, Inc. Apparatus and method for operating a real time large dipoter range sequential wavefront sensor
US8356900B2 (en) 2006-01-20 2013-01-22 Clarity Medical Systems, Inc. Large diopter range real time sequential wavefront sensor
US11762219B2 (en) * 2021-04-06 2023-09-19 Innovega, Inc. Automated contact lens design through image capture of an eye wearing a reference contact lens

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JPH04200524A (ja) * 1990-11-30 1992-07-21 Konan Camera Kenkyusho:Kk 眼球運動測定用コンタクトレンズ位置補正装置
US5686981A (en) * 1994-02-28 1997-11-11 Menicon Co., Ltd Ophthalmologic device for accurately positioning a contact lens to an eye
US5873832A (en) * 1996-08-12 1999-02-23 Xeyex Corporation Method and apparatus for measuring properties of the eye using a virtual image
DE19726888A1 (de) * 1997-06-25 1999-01-07 Woehlk Contact Linsen Gmbh Anpaßverfahren für eine Kontaktlinse und Meßlinse zur Durchführung des Verfahrens
US5963299A (en) * 1997-07-22 1999-10-05 Reyburn; Thomas P. Method and apparatus for measuring toric contact lens rotation
US20020071095A1 (en) * 2000-12-08 2002-06-13 Roffman Jefrey H. Composite surface contact lenses

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WO2004021875A1 (fr) 2004-03-18

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