Antidepressants are an effective way to combat a variety of psychological and emotional conditions, but they can sometimes have adverse side effects. A recent article in the journal Ophthalmology has revealed that there may be a link between eye disorders and two of the most widely use neural medications on the market: selective serotonin reuptake inhibitors (SSRI) and amandatine, which is used to treat Parkinson's disease.

In the first study of its kind to look at the relationship between eye disease and antidepressants, researchers compared the records of nearly 19,000 patients who were 65 years of age or older and who were suffering from heart disease. When compared to a control population, it was found that the risk for developing cataracts increased by nearly 15% when they were also taking SSRI antidepressants, which translates into about 22,000 cases.

The effect was greatest with the drugs Luvox (fluvoxamine, 39% increase), Effexor (venlafaxine, 33% increase) and Paxil (paroxetine, 23% increase). Other antidepressants did not seem to affect cataract risk, which may be the result of differences in formulations or because of an inadequate number of study participants.

The lens of our eyes contains serotonin receptors, and previous work in animal models has indicated that excessive amounts of serotonin can affect its clarity and lead to cataract formation. Though more work needs to be done to study the relationship, the findings suggest that cataract risk may need to be disclosed for seniors taking SSRIs.

In another study looking at Parkinson's patients, which is the second most common neurodegenerative disorder after Alzheimer's disease, doctors took a close look at the drug amandatine, which is used to help lessen motor difficulties over the long term. It has been known that amandatine can result in abnormal changes in the cornea of some patients. However, these changes are often temporary, and go away once treatment with the drug is stopped.

In situations of long term treatment with amandatine, it is possible for corneal problems to appear only after years of treatment. In many of these situations, the corneas do not recover even after treatment is discontinued. In order to study the possibility if this phenomenon is dose dependent, researchers compared the eyes of nearly 170 patients undergoing amandatine therapy with an equal number of controls.

What they found was that patients who took the largest amount of amandatine or took it over the longest duration (up to eight years) were the most affected in terms of their vision. The effect was most prominent in terms of the endothelial cell density (ECD) in the cornea. The ECD maintains proper amounts of water in the cornea, and when there are too few endothelial cells, as was the case with patients taking amandatine, swelling occurs and vision is consequently impaired. ECD reduction as a result of amandatine therapy did not occur right away.

The findings suggest that patients undergoing treatment for either depression or Parkinson's disease discuss any worries or concerns with the doctors, especially if they suspect that they may be suffering from problems with their vision.

For more information about cataracts or other eye disorders, visit the website for the National Eye Institute.