Keratometer

A keratometer is a diagnostic instrument for measuring the curvature of the anterior surface of the cornea, which is the main refracting surface of the human eye. The corneal curvature determines the power of the cornea and the differences in power across the cornea that results in astigmatism. Keratometery is based on the fact that the anterior of the surface of the cornea acts as a convex mirror, and by utilizing the reflective properties of the cornea, its radius of curvature can be measured. There are two types of keratometers. They are two position keratometer and one position keratometer. Keratometer is the standard instrument in ophthalmology for measuring astigmatism and finds applications in clinical uses as it offers an objective method for determining curvature of the cornea, amount and direction of corneal astigmatism, and quality and stability of the corneal refracting surface and for pre-surgical workup for cataract surgery.