Dot radial ringed placido

摘要

An ophthalmic placido pattern 10 is used to determine a curvature of an anterior surface of a cornea of an eye. The pattern 10 includes a series of alternating light and dark concentric rings 12 and 14 centered about a central point 16 . A series of shaped geometric shapes 18 and 20 are placed about at least some of the concentric rings 12 and 14 . The shapes 18 and 20 are of a contrasting color with respect to the ring 12 or 14 on which the shape 18 or 20 is placed.