What is the purpose of the cornea?

The cornea plays a critical role in vision by being the transparent front layer of the eye. Its primary function is to refract light, meaning it bends and focuses light rays that enter the eye onto the retina at the back of the eye. This refraction is essential for clear vision, as it helps ensure that images are properly focused. The cornea is also responsible for approximately 65-75% of the eye's total refractive power, making it a fundamental component in the visual process.

In addition to its refractive properties, the cornea acts as a barrier protecting the inner structures of the eye from dust, germs, and other harmful substances, but its main purpose in the context of this question is related to light refraction and focusing. Other options mention functions that are not associated with the cornea, such as tear production, connection of eyelids, or protection of eyelashes, which do not pertain to the specific functionality of the cornea.