Definition : 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.
Entry Terms : "Photokeratoscopes" , "Videokeratoscopes" , "Placido's Disks" , "Ophthalmic Measuring Instruments" , "Measuring Instruments, Ophthalmic"
UMDC code : 16347