The human body 13 remarkable in its apparent foresight in preparation for age and disease. In all parts of the body, as children we are provided with many times the necessary cells for maintenance of bodily activity. As an example, we are provided with two lungs and two kidneys when only one would suffice. Thus the fundamental concept of redundancy, heard most often in relation to the space program, is nature’s way of providing continuous bodily function as we age and suffer the many traumas of daily living.
The cornea is no different in this respect. While the cornea appears as a simple transparent surface, devoid of activity, on closer examination it becomes one of the most active and energy consuming organs of the body. In order to appreciate the diseases which affect this organ we must first consider how it functions. Our modern appreciation of the processes inherent in the functioning of the cornea is quite recent, dating from the mid 1950’s in the work of Dr. David Maurice of Stanford University. The story of his discovery and the reasoning which led to it are one of the great adventures of ophthalmology.
It has been known for several centuries that the cornea represented one potential cause of blindness as people aged.In past times diseases of the cornea were often confused with cataracts or diseases of the lens, a structure which lies behind the cornea. When corneal scars were obvious, the treatment most often employed was cosmetic, as by Galen in the early Roman period who tattooed pigment into the cornea to hide its appearance. when clinical biomicroscopy examination of the eye under magnification with a slit beam was introduced, it became possible to differentiate corneal disease from diseases of the lens. Thus a disease related to aging was described in the advanced stages by Dr. Fuchs in 1910 which developed in the following manner. As one examined older patients, one might begin to appreciate very small lumps or “guttata” on the back surface of the cornea associated with a “beaten metal” appearance when the cornea was examined with a rear illumination reflected off the iris, so called retro-illumination. That is the cornea appeared as a piece of copper night look after it had been worked with a ball-peen hammer. As these patients aged, they gradually began to lose vision and the corneas assued a very hazy appearance. By directing a slit of light across the cornea, Dr. Fuchs could estimate the thickness of the cornea and thus noted thickening of the cornea particularly in the center. In addition in advanced cases, the surface of the cornea became quite cystic with so called “bu1lae’ appearing in advanced stages.