Ocular prosthesis
An ocular prosthesis, artificial eye or glass eye is a type of craniofacial prosthesis that replaces an absent natural eye following an enucleation, evisceration, or orbital exenteration. The prosthesis fits over an orbital implant and under the eyelids. Often referred to as a glass eye, the ocular prosthesis roughly takes the shape of a convex shell and is made of medical grade plastic acrylic. A few ocular prostheses 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 or eviscerated eye. Makers of ocular prosthetics are known as ocularists. An ocular prosthesis does not provide vision; this would be a visual prosthesis. Someone with an ocular prosthesis is totally blind on the affected side and has monocular (one sided) vision.
History
The earliest known evidence of the use of ocular prosthesis is that of a woman found in Shahr-I Sokhta, Iran dating back to 2900–2800 BCE. 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. In addition to this, an early Hebrew text references a woman who wore an artificial eye made of gold (Yer. Ned. 41c; comp. Yer. Sanh. 13c). Roman and Egyptian priests are known to have produced artificial eyes as early as the fifth century BCE constructed from painted clay attached to cloth and worn outside the socket.
