Patent ID: 6190012
Filing Date: 2001-02-20
Classification: A61B

Abstract:
A cornea shape measuring apparatus comprising:(1) a pattern plate having a plurality of transparent ring-shaped patterns which is different in diameter with a plurality of masking portions therebetween;(2) a plurality of ring-shaped light sources which are disposed behind and adjacent to the pattern plate and arranged in concentric circle shape along said plurality of transparent ring-shaped patterns, thereby concentric circle pattern light as a placido pattern being projected on the cornea of the subject's eye;(3) an outer transparent ring-shaped pattern plate for making ring-shaped light out of part of the light projected from some of the plurality of light sources disposed at most exterior positions; and(4) a ring-shaped reflecting member disposed along the outer edge of the pattern plate in order to reflect the light from the outer transparent ring-shaped pattern plate.