Physiological Aging Occurs throughout the Eye and can bring about the Loss of Vision
Cindy M.L. Hutnik, MD, PhD, FRCSC
Department of Ophthalmology,
University of Western Ontario
Active Staff, St. Joseph's Health Centre, London, ON
In 1942, Sir W. Stewart Duke-Elder published his classic ophthalmic text series.1 The first paragraph eloquently describes his thoughts on the genesis of vision and the evolution of the eye "from remote and lowly origins, far removed in form and in function from the highly specialized mechanism we find in man; indeed, it is no easy matter to decide where its origin lay or when the sense of vision first became a factor in conscious behaviour." He begins by stating that "either in fact or in fiction there are few stories more fascinating than the history of the evolution of the visual apparatus from primitive undifferential protoplasm into a system of the highest delicacy and intricacy of structure." Recognizing the complexity of the human eye, the following is a summary of how this intricate structure withstands the physiological stresses of a normal human life span.
The eye is not exempt from the relentless process of aging. Structurally, changes can be observed in all parts of the eye, both macroscopically and microscopically. The key is to recognize when these structural changes begin to threaten function.