Ocular prosthesis

Overview
An ocular prosthesis or artificial eye (a type of Craniofacial prosthesis) replaces an absent natural eye following an enucleation, evisceration, or orbital exenteration. The prosthetic fits over an orbital implant and under the eyelids. Typically known as glass eyes, the ocular prosthesis roughly takes the shape of a convex shell and is made of medical grade plastic acrylic. A few ocular prosthetics today are made of cryolite glass. A variant of the ocular prosthesis is a very thin hard shell known as a scleral shell which can be worn over a damaged eye. Makers of ocular prosthetics are known as ocularists. An ocular prosthetic does not provide vision; this would be a visual prosthetic. Someone with an ocular prosthetic is totally blind on the affected side and has monocular (one sided) vision which affects depth perception.

History
In December 2006, archaeologists discovered the world's earliest artificial eyeball in Shahr-i Sokhta, Iran. It has a hemispherical form and a diameter of just over 2.5 cm (1 inch). It consists of very light material, probably bitumen paste. The surface of the artificial eye is covered with a thin layer of gold, engraved with a central circle (representing the iris) and gold lines patterned like sun rays. On both sides of the eye are drilled tiny holes, through which a golden thread could hold the eyeball in place. Since microscopic research has shown that the eye socket showed clear imprints of the golden thread, the eyeball must have been worn during her lifetime. The woman with the artificial eye was 1.82 m tall (6 feet), much taller than the ordinary women of her time. The woman's skeleton has been dated to between 2900 and 2800 BC.