What is the primary function of the cornea?

The primary function of the cornea is to focus light onto the retina, which is essential for clear vision. The cornea is the transparent, dome-shaped front surface of the eye that bends (refracts) light rays as they enter. This refraction helps direct the light toward the retina, where images are formed and transmitted to the brain for processing. The cornea offers approximately two-thirds of the eye's total focusing power and plays a crucial role in vision clarity.

While the cornea contributes to the overall structure and protection of the eye, the specific and most significant role it plays is in bending light to ensure that it reaches the retina properly. Other functions of different parts of the eye, such as the iris and the ciliary body, are more involved in regulating light entry and aqueous humor production, respectively. Therefore, focusing light onto the retina is the defining and primary role of the cornea.