system
Given the following post, respond as if you're commenting on Reddit:
human
Why can human eyes not see clearly in water?

Don't we have a, for lack of a better word, film over the cornea/iris that should allow for clear vision?
gpt
The cornea is designed to refract light as it passes through. For terrestrial organisms like us, our corneas are of the right dimensions to refract light travelling through the air into the cornea.

The water-cornea boundary has a different refractive index (bends light differently) to air-cornea so when our eyes are submerged, the light is bent at the wrong angle to be focused onto our fovea properly.