We ask the experts to settle common questions we've all wondered about.
These are clearly stressful economic times. I've heard that stress can cause problems in people's eyesight due to changes in pressure or fluid - is there any truth to that? Can stress sometimes cause a prescription change?
There may be short-term changes to one's vision during times of stress due to fatigue of our "auto-focusing" mechanism called accommodation. Accommodative fatigue may result in temporary blurred vision, headaches and eye strain. This effect is not permanent and does not usually require a change in your glasses prescription.
The changes in pressure or fluid to which you are referring are likely caused by a group of diseases known as glaucoma. There are reports in the scientific literature that stress can cause the eye pressure to increase and trigger a sudden and sometimes painful attack of "angle-closure" glaucoma. But these reports are purely anecdotal and the chance of this occurring solely because of stress is quite unlikely.
In a normal eye, fluid is produced inside the eye and circulates around the front part of the eye. There is a balance between fluid produced and fluid exiting the eye, thus exerting pressure on the eye to help maintain its proper shape. The fluid exits the eye through a drainage channel known as the "angle" of the eye.
In stressful situations, the pupil of the eye dilates or opens up. Dilation causes the iris (the coloured part of the eye) to essentially bunch up like an accordion, which narrows the drainage channel. However, such a short duration of pupil enlargement is not likely to cause a sustained rise in the pressure of the eye.
The symptoms of an attack of "angle-closure" glaucoma may include pain, blurred vision, coloured haloes around lights, headache, nausea and vomiting. If you are having these symptoms, then this may be an indication of an attack of glaucoma and you should seek help from your ophthalmologist.
Dr. Marisa Sit is an ophthalmologist at Toronto Western Hospital and a lecturer at the University
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