Expert: John Locke - 6/28/2008

Question
Nine months ago, I went started to suffer from depression and my diet became extremely poor; some days I did not eat anything other than a couple of bars of chocolate and some sweets.  After 2-3 months, I noticed that my irises have atrophied considerably and my pupils do not react to light like they should. My actual eyesight remains normal. Friends, family and my doctor refuse to see what I am concerned about - can you tell me if this is something you have ever come across?

Answer
Thanks for using AllExperts. I am not familiar with an exact condition that matches your description, but there are numerous physiological mechanisms that affect the iris and the pupil. This question also touches on some of the edges of our current knowledge relating to biological pigments, the effects of depression, and genetics. Before I continue, it is important to note that there are certain specific systemic and eye diseases that can cause a change in iris color and any marked change of short period of time requires prompt medical attention.

Exposure to sunlight, for one, can cause changes in the color of the iris--greater exposure leads to more production of the pigment melanin, with an associated darkening of the iris. If you limited your exposure to sunlight over the long term, that may have caused a reduction in the melanin pigment in your irises. There is another biological pigment known as lipofuscin that accumulates as a product of cellular metabolism; it is yellowish-brown and its accumulation is associated with color change. Blood vessel density in the eye also contributes to its color; poor diet may have led to a decrease in blood vessel density in the iris. Depression has a tremendous range of physiological effects on the body, and I suspect that it was a contributing factor, even if the underlying mechanism is not known. If you suffer from glaucoma, you may have been prescribed eye drops that are known to cause changes in eye pigments. Bimatoprost solution is used to increase the excretion of ocular fluid, thereby avoiding the high intraocular pressures associated with the disease. It is also well-recognized for causing darkening of the irises by some side effect of its action as a prostaglandin analogue.

It is difficult to identify any one of these as a proximate cause; human eye color is complex, and not all aspects of it are well-understood. Obviously, there are many contributing factors here to your situation; I wish you the best of luck in rectifying your situation.

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