The study looked at records from 500 patients, ages 60 and over, who received treatment at the university’s on-campus clinic. Data included age, general and ocular history and symptoms, antidepressant use, smoking habits, refraction, visual acuity, binocular vision and eye movement status for the most recent full oculo-visual assessment, and an assessment from 10 years prior.
The study found that about 27 percent of adults in their 60s have a binocular vision or eye movement disorder, and that number rises to 38 percent for those over age 80. Age and use of antidepressants most commonly predicted binocular vision or eye movement disorders. In addition, about 20 percent of the general population has a binocular vision disorder.
According to the university, “Conditions such as diabetes and thyroid disease are known to cause such problems, but this is the first study to link binocular vision disorders with overall general health. Similarly, other writers have discussed a possible association between certain antidepressant drugs and specific binocular vision disorders, but this is the first study to actually demonstrate a link between antidepressant use and binocular vision and eye movement disorders.
"An association does not establish that one causes the other, but rather that they co-exist," says Susan Leat, BSc, PhD, FAAO, PCOptom, who led the study. "It is possible that the effects of poor vision mean that people are more likely to take anti-depressants or make less healthy lifestyle choices."