Although tremor and rigidity are the typical symptoms of a patient with Parkinson’s disease, eye problems are quite common too, and are important because they can interfere with the quality of life of a person. When faced with eye disorders or vision problems in patients with Parkinson’s disease, it is important to bear in mind that some of these conditions may not be related to Parkinson’s. Old age, poor eyesight, complication from other chronic conditions, like diabetes, may impact on the eyesight in any person, even when Parkinson’s disease is not present.
Types of Eye Problems in Parkinson’s Disease
- Blurred vision or difficulty in focusing may be due to difficulty in moving the eyes or due to the side effects of Parkinson’s drug therapy, especially anticholinergics. This problem may occur on starting treatment with anticholinergics, but normally improves over time. It may also occur with long-term treatment with anticholinergics or after some dose adjustments.
- Double vision usually occurs in Parkinson’s disease due to problems in moving the eyes in alignment from side to side, such as when reading. This occurs as a result of impaired coordination and fatigue of the muscles moving the eyeballs.
- Excessive tearing (lachrymation) of the eyes.
- Dry eyes is caused by reduced blinking of the eyes.
- Difficulty in moving the eyes may be manifested in two ways : (i) difficulty in starting a movement of the eyes or (ii) problem with moving the eyes quickly when following a fast moving object. Instead of moving smoothly, the eyes move in a slow and jerky way. Driving a vehicle may pose difficulties.
- Sensitivity to contrast – there may be difficulty in seeing in dim light, or making out light colored objects against a light background, or difficulty in reading fine print.
- Color vision may be affected for differentiating between slight color differences, especially for shades of blue or blue-green.
- Problem with visuo-spatial orientation or depth perception – the person may have difficulty in assessing the distance between objects and may need to reach out to touch the sides of the wall or objects while walking through a narrow place. This may create problems while walking or driving.
- Glaucoma and anti-Parkinson’s medication – levodopa and anticholinergics should be used with caution in patients with glaucoma.
- Some patients with Parkinson’s disease cannot judge the speed of moving objects, which may be dangerous if driving or trying to cross the street.
- Hallucinations and illusions or visual misinterpretations are more likely to occur in those people who have had Parkinson’s disease for a long time. It may be due to the disease itself or due to anti-Parkinson drugs.
- Blepharospasm or involuntary spasm of the eyelids.
Treatment of Eye Problems in Parkinson’s Disease
- Blurred vision – modification of anticholinergic medicine dose and adjustments in power if wearing glasses.
- Double vision – improves with anti-Parkinson medicines and by resting the eye.
- Dry eyes – using artificial tear drops and avoiding dry, hot and smoky places.
- Difficulty in moving the eyes – usually improves with anti-Parkinson drugs.
- Sensitivity to contrast – improves with treatment by levodopa.
- Color vision – problem may improve with anti-Parkinson medicines.
- Hallucinations – reducing the dose of anti-Parkinson drugs and use of neuroleptics such as clozapine and quetapine.