Certified Ophthalmic Assistant Practice Exam 2025 - Free Ophthalmic Assistant Practice Questions and Study Guide

Keratometry measures the curvature of the anterior surface of the cornea, which is crucial for various aspects of eye care, including contact lens fitting and preoperative assessments for cataract surgery or refractive procedures. The results are expressed in terms of curvature power, which is measured in diopters.

Diopters represent the optical power of a lens and are inversely related to the focal length in meters. For keratometry, the power of the cornea is derived from its radius of curvature; the steeper the cornea, the shorter the radius and the higher the diopter measurement. Therefore, diopters effectively convey how much the cornea converges light, which is key for understanding corneal refractive characteristics and its influence on vision correction.

While millimeters, centimeters, and degrees may relate to physical measurements or angles, they do not accurately convey the optical power aspects essential for evaluating corneal curvature. Thus, the use of diopters provides a standardized and clinically relevant measure for keratometric results.