NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Press Enter or click the Search button to begin your search.

Back to Results
Real-time analysis keratometerA computer assisted keratometer in which a fiducial line pattern reticle illuminated by CW or pulsed laser light is projected on a corneal surface through lenses, a prismoidal beamsplitter quarterwave plate, and objective optics. The reticle surface is curved as a conjugate of an ideal corneal curvature. The fiducial image reflected from the cornea undergoes a polarization shift through the quarterwave plate and beamsplitter whereby the projected and reflected beams are separated and directed orthogonally. The reflected beam fiducial pattern forms a moire pattern with a replica of the first recticle. This moire pattern contains transverse aberration due to differences in curvature between the cornea and the ideal corneal curvature. The moire pattern is analyzed in real time by computer which displays either the CW moire pattern or a pulsed mode analysis of the transverse aberration of the cornea under observation, in real time. With the eye focused on a plurality of fixation points in succession, a survey of the entire corneal topography is made and a contour map or three dimensional plot of the cornea can be made as a computer readout in addition to corneal radius and refractive power analysis.
Document ID
20080008183
Acquisition Source
Jet Propulsion Laboratory
Document Type
Other - Patent
Authors
Adachi, Iwao P.
Adachi, Yoshifumi
Frazer, Robert E.
Date Acquired
August 24, 2013
Publication Date
September 8, 1987
Subject Category
Optics
Report/Patent Number
Patent Application Number: US-PATENT-APPL-SN-549157
Patent Number: US-PATENT-4,692,003
Funding Number(s)
CONTRACT_GRANT: NAS7-918
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Patent
US-PATENT-4,692,003
Patent Application
US-PATENT-APPL-SN-549157
No Preview Available