Source:http://linkedlifedata.com/resource/umls/id/C0181448
UMD: Ophthalmic measuring instruments designed for objectively determining the curvature of the anterior corneal surface and refractive error (astigmatism) by projecting concentric rings on the cornea. These devices typically consist of a circular disk with a series of concentric rings (also known as Placido's disk) whose images are projected onto the cornea. The reflected images of the rings are viewed by the examiner and/or are recorded using a video camera (videokeratoscope) or a still film camera (photokeratoscope) for later examination. Keratoscopes are used mainly for preassessment for refractive corneal surgery, contact lens fitting, or diagnosis of some corneal disorders.