What is "keratoscope"

n. (context ophthalmology English) An ophthalmic instrument for assessing the shape of the anterior surface of the cornea.

n. medical instrument to examine the cornea in order to detect irregularities in its anterior surface

A keratoscope, sometimes known as Placido's disk, is an ophthalmic instrument used to assess the shape of the anterior surface of the cornea. A series of concentric rings is projected onto the cornea and their reflection viewed by the examiner through a small hole in the centre of the disk. A regular-shaped cornea should show equally spaced symmetric reflections. If the patient is suffering from astigmatism or from a corneal dystrophy, the rings will be distorted.

A modern development of the concept is found in corneal topography, in which analysis of the reflected image is passed to a computer. The automated instrument can produce colour-coded contour maps of the eye's topography or even three-dimensional visualisations of its surface.

Category:Ophthalmology Category:Ophthalmic equipment