Ophthalmic testing devices
AssigneeRandwal Instrument Co., Inc.
InventorPaul W. Remijan
Life of this patent
Estimating the term…
Abstract
Optical measuring and testing apparatus incorporates a holographically recorded, single-frequency, optically thin phase grating. When this phase grating is illuminated by a quasi-monochromatic, spatially coherent light source, it acts as a basic common path interferometer and constitutes a highly efficient source for a high contrast, stable, interference fringe pattern. Various apparatus embodiments incorporating the phase grating are described which permit (1) measurement of central and peripheral retinal acuity, (2) variable contrast testing to measure the ability of the eye to detect low contrast stimuli, (3) measurement of visually evoked responses to help diagnose retinal-neurological dysfunction, and (4) the testing of optical lenses.
Claims43
Opthalmic apparatus for producing an interference pattern on the retina of an eye, said apparatus comprising:
- A. interference pattern generating means for generating a first diffraction and a second diffraction that have equal strength, that overlap and the absolute values of whose order numbers are different thereby to produce a high-contrast, low-noise interference pattern in the area of overlap;
- B. focusing means positioned on an axis to receive the interference pattern from said interference pattern generating means for projecting the interference pattern onto the retina from only two point sources of light in the eye pupil;
- and
- C. means for affecting the interference pattern produced on the retina.
Dependencies are inferred from the claim text.