Cooperative eye hypothesis Cooperative eye hypothesis The cooperative eye hypothesis is a proposed explanation for the appearance of the human eye. It suggests that the eye's distinctive visible characteristics evolved to make it easier for humans to follow another's gaze while communicating or while working together on tasks. Unlike other primates, human beings have eyes with a distinct colour contrast between the white sclera, the coloured iris, and the black pupil. This is due to a lack of pigment in the sclera. Other primates have pigmented sclerae that are brown or dark in colour. There is also a higher contrast between human skin,
Enucleation of the eye To avoid a sunken appearance to the eye socket, an implant approximating this volume can be placed into the space of the removed eye, secured, and covered with Tenon's capsule and conjunctiva (the mucous membrane covering the natural sclera). Implants can be made of many materials with the most common being plastic, hydroxylapatite, metal alloy or glass. Later, once the conjunctiva have healed and post-operative swelling has subsided, an ocular prosthesis can be placed to provide the appearance of a natural eye. The prosthesis is fabricated by an ocularist. Its form is that of a cupped disc so that it