Optics: eye examining – vision testing and correcting – Eye examining or testing instrument
Patent
1999-04-06
2000-02-08
Manuel, George
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
A61B 310
Patent
active
060221070
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process and system for determining the topography of eye reaction signals, for which a luminous image is represented on a surface consisting of surface segments placed before the eye, where each surface segment is controlled to be bright or dark through a time function assigned to it and, at the same time, the total eye reaction is measured.
The topography determined for the eye reaction signals shows the objective sensitivity of the retina and thus provides information on the ability to see. With such examination, early recognition and evaluation of eye diseases, for example glaucoma, is possible. Above all, such examinations can detect partial defects in the retina.
There are many methods of examination, which work on a subjective basis, that is, in which the person examined evaluates the measurement by his statement. In all these methods, the patient is integrated into the measurement by making statements as to whether and how he experiences a certain stimulus.
The electroretinogram (ERG) has been established as an objective measuring procedure, in which the reaction signal is taken from the eye by means of an electrode represented with its progress over time and evaluated. One-time flashes of light or light-dark sequences (flicker ERG) are used as stimuli. At the same time, the average value for the entire surface of the retina is determined. In recording the potentials evoked, electrodes are applied to a certain point on the head and the signal measured corresponds to the reaction, which occurs through bundles of nerve fibers at the measuring position. Details on this have been published by J. Jorg and H. Hielscher in the book "Potentials Evoked in Clinic and Practice," Springer Publishing House.
To determine the topology of the retinal sensitivity, the possibility exists basically of stimulating surface segments of the retina with individual light stimuli aimed at surface segments and measuring the reaction. Since average values must be formed in order to reduce measurement error, this process results in an intolerably long measuring time.
In U.S. Pat. No. 5,382,987, the coupling of an ophthalmoscopic device on the basis of a three-way Maxwell observation system is suggested for the optical examination of the retina of the eye, with a perimeter arrangement to determine the field of vision, where the spectral sensitivity of a selected portion of the retina can be measured with the aid of the electroretinogram, for which a stimulus pattern is transferred to the retina. With this process, the sensitivity of an individual portion, as well as the overall picture of the retina, can be examined. For the measuring examination of all parts of the retina, this would also result in an intolerably long examination time.
The use of a laser projector, provided with an optical modulator for the generation of a brightness pattern on the retina for the measurement of the pattern electroretinogram (PERG), is provided by Daniel R. Peters and John Tabora in the U.S. Pat. No. 5,233,373. With this, however, only a selected surface of the retina can be examined and the examination of multiple surfaces can be done only sequentially.
An improved process in the associated system for determining the distribution of functions of the reaction to stimuli over the surface of the retina was provided by R. Richardson in EP 0 375 737. Here, the overall reaction of the retina to stimuli in the field of view is recorded, where the stimuli are formed by series of patterns whose intensity changes in both horizontal and vertical directions. As an example, a sine or cosine wave distribution of intensity is used and, by back transformation from the measured overall signals, the distribution of sensitivity over the surface of the retina can be calculated. The disadvantage of this process is that measuring errors in the determination of the individual coefficients cannot be recognized, but individual measurement errors affect the calculation of the entire distribution function. Also disadvantageous in this process i
REFERENCES:
patent: 4822162 (1989-04-01), Richardson et al.
patent: 4846567 (1989-07-01), Sutter
patent: 5233373 (1993-08-01), Peters et al.
patent: 5382987 (1995-01-01), Sperling
patent: 5539482 (1996-07-01), James et al.
patent: 5632282 (1997-05-01), Hay
B. Brown et al.: "Contrast and luminance as parameters defining the output of the Veris topograhical ERG", Ophthalmic & Physiological Optics, vol. 16, No. 1, Jan. 1996, pp. 42-48.
E.E. Sutter et al.: "The Field Topography of ERG Components in Man",Vision Research vol. 32, No. 3, 1992, pp. 433-446.
S. Parks et al.: "Comparison of repeatability of the multifocal electroretinogram and Humphrey perimeter", Documenta Opthalmologica, vol. 92, 1997, pp. 281-289.
Guenther Ralf
Held Uwe
Hinkel Albrecht
Hoch Uwe
Kutschbach Ernst
Cindatec Ingenieurtechnische Dienste GmbH
Manuel George
LandOfFree
Process and system for determining the topography of eye reactio does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process and system for determining the topography of eye reactio, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process and system for determining the topography of eye reactio will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1675906