Abnormal binocular vision, which involves the way eyes work together as a team, increases dramatically as we age, according to research from the University of Waterloo. The study also found a correlation between this condition, general health and antidepressant use.
As many as 27 per cent of adults in their sixties have an actual binocular vision or eye movement disorder. That number rises to 38 per cent for those over age 80. About 20 per cent of the general population suffers from a binocular vision disorder, which affects depth perception and therefore may increase the risk of falls.
Dr. Susan Leat, a professor at the School of Optometry and Vision Science at Waterloo led the study, which looked at randomly selected records from 500 older patients over age 60 who received treatment at the school's on-campus clinic.
"Thirty to 40 per cent of the population is an exceptionally high rate of incidence for any disorder," said Dr. Leat.
This is the first study to quantify binocular vision loss with age and show a connection with antidepressant use and general health. 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," said Dr. Leat. "It is possible that the effects of poor vision mean that people are more likely to take antidepressants or make less healthy lifestyle choices."
Although the study suggests that the rate of binocular vision disorders in older adults is higher than expected, there is good news. Many binocular vision disorders are treatable with glasses, vision therapy, or in some cases surgery.
"Keeping your glasses up-to-date through regular eye examinations to avoid large prescription changes is one way to maintain good vision, decrease risk for falls and maintain a good quality of life as you age," said Dr. Leat.
Optometry researchers, Dr. Lisa Chan, Dr. Priya-Devi Maharaj, Dr. Patricia Hrynchak, Andrea Mittelstaedt, Dr. Carolyn Machan, and Dr. Elizabeth Irving co-authored the paper and the results were published in the journal Investigative Ophthalmology and Vision Science. The Vision Services Plan and the Canadian Optometric Education Trust Fund supported the research.