FLICKR, GAELG. As has been found in some bird and primate species, human eye and visual system sizes vary with the levels of ambient light in a given environment, according to a study published ...

In the human eye, the cornea is the clear, dome-shaped portion located at the front of the eye that is responsible for focusing light, according to the American Academy of Opthalmalogy (AAO).

Scientists have created the first 3D model of the human conjunctiva — the clear, protective outer membrane of the eye — in the lab, and it even produces its own tears.