Artificial Eye

ARTIFICIAL EYE, first described and used as a prosthesis to replace a missing eye by Ambroise Paré in 1579. Some historical documents indicate that artificial eyes were made even in antiquity, though not for living people, but for mummies (Egypt) and statues (Greece). In any case, references to the use of artificial eyes as prostheses in living people before Paré are untrustworthy. The first eyes were made of gold, coated with white enamel with a painted iris and pupil. Beginning in the 18th century, glass prostheses appeared on the market. An attempt was made to replace glass with celloidin, but it failed. In its external appearance, Paré's artificial eye was very similar to modern prostheses, which have the shape of a small oval cup. Today, exclusively two types of eyes are used: the ordinary cup-shaped prosthesis, made from a single piece of glass, and the double "Reformauge" prosthesis, which has the same appearance from the front as the ordinary prosthesis, while on the inner side it has a second glass plate, thanks to which the depression is very slight and the edges are more rounded. Such a prosthesis is much more durable and better tolerated. The edges of the artificial eye must fit snugly against the conjunctiva. The anterior surface contacts the posterior part of the eyelids. The lower edge of the prosthesis presents a regular curved line, while the upper one has a small notch facing the upper-inner part of the orbit. The thickness of the glass of the prosthesis is 0.5–1.0 mm at the periphery and from 2 to 3.5 mm in the region of the iris. At the beginning of the 19th century, the best prostheses were made in France, which was the main supplier of this commodity. Then Germany began to compete with it and almost completely displaced it from the world market. Prostheses are manufactured in the following manner: the worker blows a small bubble of glass enamel at the end of a metal tube. Then, without removing it from the tube, they paint the design of the iris on the top of the hot sphere using multicolored enamel pencils, in the middle of which a drop of black enamel is placed to depict the pupil. Next, the upper half of the sphere is given the desired shape of the prosthesis and finally cut off using a hot metal rod. After giving the edges a rounded shape, the resulting prosthesis is slowly cooled. An artificial eye must satisfy the following conditions: it must not be felt by the patient when worn, it must be (as far as possible) similar to the other eye, its edges must be rounded and completely smooth, the anterior and posterior surfaces must be polished, and it must have no roughness. The prosthesis must not protrude forward or sink in, but must fit snugly against the stump in order to move within certain limits together with the healthy eye. Patients are advised to remove the prosthesis at night and keep it in a borax solution. As soon as the artificial eye begins to deteriorate (appearance of cracks, roughness, etc.), it must be replaced with a new one. The usual period of wearing a single prosthesis is 2–3 years. The prosthesis is inserted in the following manner: one hand grasps the upper eyelid by the eyelashes, lifts it, and guides the upper edge of the prosthesis under it. Then the lower eyelid is pulled back enough so that it falls in front of the lower edge of the prosthesis. If the eyelids are then released, the artificial eye assumes its normal position in the orbit. When removing the prosthesis, the lower eyelid is pulled back and a hairpin or metal rod is inserted between it and the eye. The prosthesis pops out by itself; if it does not come out, the upper edge of the upper eyelid is pressed lightly.