In what unit is keratometry expressed?

Keratometry is a measurement of the curvature of the cornea, and it is expressed in diopters. The diopter is a unit that quantifies the refractive power of a lens or mirror, which is directly related to how the curvature of the cornea affects light refraction. Specifically, it is calculated as the reciprocal of the focal length measured in meters. Since keratometry measures the way light bends as it passes through the curved surface of the cornea, diopters provide a standardized way of expressing this relationship, helping eye care professionals assess the visual power of the cornea adequately.

The other units mentioned, such as millimeters, degrees, and centimeters, relate to different measurements that do not directly indicate the refractive power associated with the corneal curvature. Millimeters and centimeters refer to linear measurements of distance, while degrees pertain to angular measurements. Therefore, while these units may have their own significance in various aspects of optics or anatomy, the use of diopters specifically pertains to the measurement of curvature in keratometry.