Optics: eye examining – vision testing and correcting – Spectacles and eyeglasses – Ophthalmic lenses or blanks
Patent
1991-02-19
1993-10-12
Arnold, Bruce Y.
Optics: eye examining, vision testing and correcting
Spectacles and eyeglasses
Ophthalmic lenses or blanks
351205, 351206, 351219, G02C 704
Patent
active
052529983
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to an instrument for the examination or the treatment of the eye with an examination device designed for examining the fundus oculi and with a contact eyeglass having a lens, which is to be placed on the eye and the surface of which that faces the eye is adapted to the curve of the cornea.
STATE OF THE ART
An instrument of this kind is known from the U.S. Pat. No. 4,213,678. In this prior art instrument, the optical power of the contact eyeglass, which is provided with two spherical surfaces, is taken into consideration in the calculation of the path of the beam of the actual examination device, which in this case is a scanning laser ophthalmoscope, so that the contact eyeglass is an indispensable part of the beam path.
However, there are a number of examination and treatment situations, in which the use of a contact eyeglass is troublesome:
One source, by way of illustration, is that the examining person has to hold the contact eyeglass with one hand thereby restricting him/her in handling the examination device and/or in performing other manipulations.
Furthermore, there are certain examination and/or treatment situations, in which an as large as possible "free space", i.e. an as large as possible distance between the apex of the eye and the apex of the final surface of the eye examination device, i.e. of the surface lying closest to the eye, is required.
For this reason, instruments for the examination and treatment of the eye have increasingly been proposed whose beam path is designed in such a manner that use of a contact eyeglass is obviated. Only by way of example, reference is made to the U.S. Pat. Nos. 4,764,005, 4,768,873 and 4,854,692 as well as EP-A 0145 563 in which scanning laser ophthalmoscopes are described which do not use a contact eyeglass.
Moreover, contact eyeglasses are known from DE-A-37 18 599 or the U.S. Pat. Nos. 4,560,962, 4,598,984, 4,664,490 or 4,728,183. These contact eyeglasses, however, are intended for the examination and/or treatment of the fundus oculi with an examination device, the optical design of which "actually" only permits the examination of the anterior portions of the eye. Examination devices of this type are, by way of illustration, slit lamp devices built in accordance with the optical design of the so-called slit lamp microscope for the examination of the cornea and the anterior portions of the eye. The use of these contact eyeglasses permits extending the area of application of such instruments even to the examination and/or treatment of the fundus oculi. The contact eyeglasses known from the aforementioned publications can, however, not be utilized in connection with eye examination devices designed to examine and/or treat the fundus oculi as "adding" the power of this examination device to the power of the contact eyeglass would yield an optical power that would make sharp focussing on the fundus oculi impossible.
It has turned out that ophthalmogists prefer slit lamps with additional contact eyeglasses as the instrument of examination, respectively of observation in laser treatment of the fundus oculi to devices, which are actually intended for the examination of the fundus oculi and with which no additional contact eyeglass is employed.
In accordance with the present invention it was understood that the reason therefor is probably that there are a number of problems involved in treating the fundus oculi without using a contact eyeglass:
By way of illustration, problems due to blinking, inevitable eye agitation and drying of the cornea from holding the eye open for longer periods without blinking as, by way of illustration, is the case when the eye is held open by a clamp. The drying of the cornea makes it deform and the image worsens substantially thereby.
DESCRIPTION OF THE INVENTION
The object of the present invention is to solve the problems arising from blinking, eye agitation, etc, especially, in laser treatment of the fundus oculi with an instrument designed for the examination of the fundus ocul
REFERENCES:
patent: 4134647 (1979-01-01), Ramos-Caldera
patent: 4410245 (1983-10-01), Koester
patent: 4728183 (1988-03-01), Heacock et al.
patent: 5046836 (1991-09-01), Volk
Plesch Andreas
Reis Werner
Wilms Karl-Heinz
Arnold Bruce Y.
Dang Hung X.
G. Rodenstock Instruments GmbH
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