In the Eye of the Beholder: Sight, Illusion and Disorder
Pathology
| The retina, a thin tissue the size of a postage stamp at the back of the eye, is the key to sight; damage to this tissue by injury or disease can cause loss of vision. Photographs of the retina accompany descriptions of seven common diseases. When compared with a normal retina, these photographs illustrate the subtle changes in the anatomy of the eye that can cause vision loss.
Diabetics face the risk of retinal damage, while a blow can detach the retina; aging
sometimes causes the center of the retina to break down slowly stealing vision.
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4. A sixteenth century strategem for treating
crossed eyes. Courtesy of the World Health Organization, Geneva, Switzerland.
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| Various disorders may also affect other parts of the eye. A cataract causes the lens to become cloudy. Glaucoma occurs when drainage canals become blocked. Or the eyes may stop moving in tandem, each sending a different signal to the brain; ultimately, the brain rejects the image from one eye to avoid confusion.
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5. Clockwise from left: Gonioscope, 1946; Gonioscope, 1944, Gonioscope, 1944, all from the collection of Lee Allen, Iowa City. |
6. An eye after corneal transplantation. Photograph courtesy of Jay H. Krachmer, MD |
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7. Sixteenth century cataract surgery.
Courtesy of the World Health
Organization, Geneva, Switzerland. |
| 8. Cataract removal instrument pictured in the Ten Books of Surgery (1564) by Ambroise Pare. New York Academy of Medicine. |
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