In what unit is keratometry expressed?

Keratometry is a measurement that assesses the curvature of the cornea, which is crucial for fitting contact lenses and determining certain surgical procedures. The results of keratometry are expressed in diopters. This unit reflects the refractive power of the cornea; the steeper the curvature, the higher the diopter value, indicating more power in bending light. This physiological measurement helps eye care professionals evaluate vision corrections. While other units like millimeters refer to linear measurements (and are sometimes used in the physical measurement of corneal curvature), diopters specifically quantify the optical power, making them the appropriate unit for keratometry. Degrees and centimeters do not apply to this context, as keratometry is concerned with curvature and refractive power rather than angular measurements or linear dimensions.