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by Philip Filner, Ph. D.
What we call a disorder influences our attitude and actions concerning it. Until about a decade ago, Age Related Macular Degeneration was often called Senile Macular
Degeneration by ophthalmologists. Imagine telling someone you were afflicted with Senile Macular Degeneration. Their first thought would probably be, "Oh my. (S)he's senile
!" , because non-doctors only use "senile" to refer to deterioration of the mind of elderly people. Using the term "Senile Macular Degeneration" was
misleading because there is no connection between senility and macular degeneraton, other than that both become more probable with increasing age. Out of consideration for how others
would perceive their patients, most ophthalmologists switched to the term, "Age Related Macular Degeneration (ARMD)".
The development of research on senility is a
model of what we would like to see happen to research on ARMD. For a long time, senility was thought to be something that just happened naturally to some people when they got old. It
was not thought of as a potentially preventable, treatable disease. Thirty years ago, there was a rather rare disease in young people, called premature senile dementia, in which the
minds of afflicted young people deteriorated the way the minds of some elderly people deteriorated. This rare disease of young people had another name: Alzheimer's disease. When
researchers studying Alzheimer's disease examined samples of brain tissue from deceased young people who had Alzheimer's disease, with an electron microscope, they discovered unusual
structures which were named "plaques". When samples of brain tissue from deceased senile elderly people were examined by the same technique, the same unusual plaques were
seen. It was a revelation: senile dementia was Alzheimer's disease in elderly people, not a normal event in aging. It was not a rare disease, but rather a very common one which
afflicted many people late in life. Because of this discovery, research on how to prevent and treat Alzheimer's disease became a high priority for the biomedical community. Research
on Alzheimer's disease greatly increased in scope, scale and pace. Progress is being made.
Names can be confusing
Calling the disorder we are interested in "Age Related" again suggests to many
people, including many ophthalmologists, that it is a normal part of aging, rather than a disorder/disease which is potentially preventable and treatable. However, as in the case of
Alzheimer's disease, there are rare forms of macular degeneration which afflict young people. These forms, such as Best's disease, Stargardt's disease, Sorsby's disease, and the cblC
type of cobalamin deficiency, are hereditary. Each is caused by a mutation in a gene. Excellent molecular genetic research is being done on some of these disorders. We can expect
important insights into both hereditary and age related macular degenerations to come from this research. When a good lead is found to the cause of an hereditary macular degeneration,
it should stimulate research to determine if the same mechanism operates in ARMD. Finding such a lead should trigger a major increase in research on ARMD.
A genetic disorder
which leads to macular degeneration, even before there is detectable deterioration of central vision, is called a "maculopathy" or "macular dystrophy". These terms
are also used when symptoms thought by some to be pre-macular degeneration conditions, are seen in the retinas of elderly people who have not suffered substantial deterioration of
central vision. To make matters a little more confusing, the terms "maculopathy" and "macular dystrophy" are essentially generic terms for disorders of the macula,
so are also sometimes used for conditions of the macula of the retina unrelated to macular degeneration.
Medical Naming Needs Improvement
In eye anatomy, it turns out that the term "macula" is also used to
refer to the center of the cornea. There is a disorder of the cornea called "Macular Corneal Dystrophy", which in some research reports gets shortened to "Macular
Dystrophy". Yes, believe it or not, ophthalmologists use the same term for two entirely different disorders of the eye. |
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