What is the focal power of the cornea?

The focal power of the cornea is approximately 43 diopters. This is due to the cornea being the primary refractive surface of the eye, playing a critical role in focusing light onto the retina. The cornea’s curved shape and its index of refraction contribute to its strong refractive power. Normally, the cornea accounts for about two-thirds of the eye’s total optical power, with the rest being contributed by the crystalline lens, which is adjustable and helps in fine-tuning the focus.

Understanding this number is important for various aspects of vision care, including the fitting of contact lenses, understanding refractive errors, and planning surgical procedures such as LASIK. The high refractive power of the cornea allows it to effectively bend light entering the eye, ensuring clear vision when properly functioning.