In Part 1 we learned about eye movement disorders that affect People with Parkinson’s disease. In this blog we will learn about disorders that affect the eye itself and the external eye.
Good news: These issues don’t affect every person with PD, but it’s important to recognize these issues and the variety of ways to treat them.
Here are visual issues and treatments that can affect people with PD
Abnormalities of blinking
The blink reflex, (which is normally about 16-18 times per minute), may decrease in PD, sometimes substantially. Less commonly blepharospasm, or excessive blinking, may happen. Occasionally, there is apraxia of eyelid opening, which is an inability to open the eyes voluntarily.
People with PD who have blepharospasm may benefit from injections of Botox in the muscle surrounding the eye. This treatment is usually repeated every three to four months and can be very effective. Those with apraxia of eyelid opening can also sometimes benefit from Botox injections.
External eye disease
Decreased blinking can cause dry eyes. In addition, due to the dysfunction of the autonomic nervous system, blepharitis, or irritation of the eyelids can occur.
Blepharitis can be managed with warm, moist compresses, lid scrubs, and/or medicated ointments. Dry eyes can be treated with artificial tear substitutes. These treatments can be very effective in making the eyes look and feel better, and increase vision.
Sensory deficits
Dopamine neurons in the retina can also be lost in PD. The dysfunction of these neurons can make it more difficult to distinguish between items that are of similar color intensity.
There can also be color vision deficits, usually along the blue-yellow axis, that makes it harder to distinguish certain colors from others. Visual disturbances, such as visual hallucinations can also occur. Although it is harder to treat the sensory deficits, sometimes certain lens tints can be helpful.
Medications May Affect the Eyes
All prescriptions have potential side effects, and some involve vision.
Anticholinergic medications, such as Artane (trihexyphenidyl) — used to treat tremor — can lead to dry eyes and blurred vision. Treatments include eye ointments or drops, or warm compresses. If symptoms are severe, it may be necessary to switch medications.
In some cases, hallucinations (seeing things that aren’t there) and illusions (misinterpreting things that are there — thinking a tree is a person etc.) may occur. These visual symptoms can also be a side effect of some Parkinson’s medications. In general, they are more likely to happen in people who have ongoing problems with their vision (they need corrective lenses or have other conditions affecting the eyes, for instance).
Remember, people with PD can still get the garden variety ophthalmologic diseases. With proper attention and routine eye care, people with PD can protect and improve their vision.
If you’re experiencing changes in your sight, don’t automatically blame it on age or Parkinson’s. Ask your doctor what could be causing your symptoms and what treatments are available. Don’t hesitate to ask for a neuro-ophthalmologist if the symptoms persist.
Did you miss Part 1 of this blog series? Click Here To Read Part 1
References:
https://www.apdaparkinson.org/what-is-parkinsons/symptoms/eye-vision-issues
www.michaeljfox.org/foundation/news-detail.php?ask-the-md-vision-and-parkinson-disease
www.parkinsonsvic.org.au/parkinsons-and-you/smell-and-vision