04/06/2009 - Articles
Vision Problems in Parkinson's Disease
By: Robert W. Griffith, MD

Eye problems are not uncommon in people suffering from Parkinson's disease. 
In such cases it's important to recognize that Parkinson's may be 
responsible, in order to prevent unnecessary surgery and obtain the most 
appropriate treatment.

Eye problems are not unusual in people with Parkinson's disease. Dr Jay B 
Lavine is an ophthalmologist from Tucson, Arizona, USA, who has written a 
most helpful article in the latest Educational Supplement published by the 
American Parkinson Disease Association. We reproduce it in full here. Robert 
Griffith, Content Editor, HealthandAge.com.
Vision Problems and Parkinson's Diseaseby Jay B Lavine, MD

Symptoms

Stiffness and tremor are the hallmarks of Parkinson's disease (PD), but eye 
problems can also interfere with quality of life as well. People with 
Parkinson's usually develop a stare because they don't blink as frequently 
as they used to and involuntary closing of the eyelids is also a frequent 
occurrence. Eye movement disorders are apparent on examination, although 
they do not always cause problems from a functional standpoint. For example, 
the eyes may not move much in an upward direction, something that occurs to 
a lesser degree in many people as they age, but this may not bother most 
people. The eyes may have difficulty fixating on objects and following them 
as they move. Occasionally, because of a lack of eye coordination, people 
experience double vision, which may be present only when looking in certain 
directions. Most commonly, this occurs at the reading distance and is called 
convergence insufficiency. Some people who have this problem do not complain 
of double vision, but say that their eyes tire quickly when they read or 
that the words start to run together. These problems are all caused by the 
degeneration in the brainstem of people with PD. This degeneration results 
in low levels of dopamine, an important chemical messenger in the brain.
The degenerative changes may cause other problems as well. Special tests 
measuring electrical activity in the eye and in the brain, such as the 
visual evoked potential (VEP) and the electro-retinogram (ERG) have shown 
abnormalities in people with Parkinson's. Symptoms caused by these 
abnormalities include reduced vision, poorer color vision, and difficulty 
appreciating the correct location or orientation of an object. It is not 
clear whether all of these vision problems are the result of the 
degeneration in the brain or whether some may be due to lowered dopamine 
levels in certain cells of the retina (lining of the back wall of the eye 
that transmits images to the brain via the optic nerve).
Although not all vision problems may be treatable, it is important that 
their cause be recognized so that unnecessary surgical procedures, such as 
cataract surgery, are not performed.
Many people, especially those with more advanced Parkinson's disease, suffer 
from visual hallucinations. They may sometimes see people, animals, or 
objects that aren't really there. The hallucinations may be in color or in 
black and white, and they may be moving or still. They can cause frustration 
and can be very debilitating for some people. Again, degenerative changes in 
the brain play a role, although the drugs used to treat PD can, in 
themselves, contribute to the problem.
The lack of blinking often causes problems, especially with reading. 
Blinking is necessary to keep the front surface of the eye moist and to 
preserve the quality of the tear film that coats the cornea (front surface 
of the eye). With inadequate blinking, the tears bead up on the cornea with 
dry spots in between these watery islands, much as you might see on a newly 
waxed car. This can cause discomfort and interfere with vision. Furthermore, 
without the windshield wiper-like motion of the eyelids, the quality of the 
tear film suffers greatly. Oily debris builds up within the tear film, 
creating a ""dirty" tear film. This destabilizes the tear film and allows 
the dry spots to appear on the eye even sooner than they would otherwise. As 
a result of these problems, along with the dryness of the eyes that often 
accompanies aging, people with PD may have difficulty reading and seeing 
clearly in general. A competent ophthalmologist can measure both the 
quantity and the quality of the tears. Again, it is important to recognize 
the cause of these problems so that unnecessary surgery is not done.

Treatment

Preservative-free artificial tear eye drops, sold over the counter, can be 
used as a way of lubricating the eye and temporarily improving the quality 
of the tear film. However, because of the involuntary spasmodic closing of 
the eyelids that is often present, it may not always be easy to instill the 
drops. And the effect of the drops may be for no more than fifteen minutes. 
It's fine to use the drops that frequently, provided they are the 
preservative-free kind. These drops lack the chemicals that can irritate the 
eye when drops are used more than two or three times a day. They are 
packaged in single-use containers, usually about thirty to the box. 
Different brands use different formulations, and no onebrand can be 
recommended for everyone. Everyone's tears are different in terms of their 
acidity, viscosity, salt content, etc. Try different ones and see which one 
works best for you. Using an eye-wash to flush out the debris and wet the 
eye may also be helpful.
Double vision problems may be difficult to treat. Eye muscle exercises are 
not usually helpful. Prisms, which are special lenses that help keep the 
eyes in alignment, are worth trying. They can be part of an eyeglass 
prescription, but temporary paste-on prisms called Fresnel lenses can be 
used on a trial basis. If that doesn't work, there is one surefire remedy 
that never fails to eliminate the double vision: occlusion (covering up) of 
either eye. Don't dismiss this alternative out of hand. There is no law that 
says you have to use both eyes together all the time! There are ways of 
occluding an eye that are barely noticeable to other people. Translucent 
patching materials and even clear nail polish applied directly to an 
eyeglass lens can do the trick. Sometimes just part of one lens needs to be 
occluded, allowing unobstructed vision throughout the balance of the lens.
If you have hallucinations, report them to your medical doctor. Sometimes 
adjustment of your medication dosage can lessen the problem. If they are 
becoming debilitating, medication that can suppress the hallucinations 
without worsening other Parkinson's symptoms can be prescribed. Two of the 
more promising drugs are clozapine and quetiapine. Like most medications, 
they can have side effects. For example, clozapine may rarely cause the bone 
marrow to stop making certain white blood cells, and quetiapine can 
occasionally cause dizziness or rarely fainting because of low blood 
pressure. Therefore, the patient must be closely monitored by the attending 
physician.
The ultimate solution to the eye and vision problems seen in Parkinson's 
disease will be better treatment of the underlying disease or even 
prevention. Better drugs are being developed and a dietary approach can be 
valuable as well. Many patients with Parkinson's disease develop the on-off 
syndrome, in which the symptoms of the disease come and go. Higher protein 
diets seem to contribute to the problem, inhibiting the absorption of 
L-dopa-containing medication such as Sinemet® and interfering with its 
ability to enter the brain. A fiber-rich, plant-based diet, containing large 
amounts of vegetables, fruits, whole grains, and nuts, is lower in protein 
than the overly rich average American diet and can help alleviate this 
problem. At the same time, it can lessen constipation and promote heart and 
bone health.

Conclusion
Some of the vision problems occurring in people with Parkinson's disease may 
seem daunting to some, but don't let them overwhelm you. Never give up!
Educate yourself about what can be done, including what you can do for 
yourself. This is especially important in today's health care environment. 
Instead of focusing on your limitations, focus on what you can still do and 
make the most of it!
Source

Lavine JB. Vision problems and Parkinson's disease. American Parkinson 
Disease Association, Inc. 1250 Hyland Blvd. Ste 4B, Staten Island, NY 10305. 
Educational Supplement #17, 2002.
The American Parkinson's Disease Association
Parkinson's Disease - Dealing With 'Wearing-Off'

Rayilyn Brown
Director AZNPF
Arizona Chapter National Parkinson Foundation
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