The Parkinson’s Disease Foundation (PDF) hosted a symposia on Parkinson’s on July 18, 2008. The overall topic is “Mind, Mood and Body: Understanding Nonmotor Symptoms of PD.” Here’s a link to the archived recording of the symposia:
One of the panelists, Dr. John Goudreau, gave a good, albeit short, presentation on the topic of “Visual Impairment in Parkinson’s Disease.” He is a neuro-ophthalmologist at Michigan State University.
Copied below are the notes I took from his talk along with relevant Q&A. (The time markers refer to the time in the recording, if you want to refer to the original.)
Speaker: John L. Goudreau, D.O., Ph.D., Michigan State University
Visual impairment is a common complaint in PD and ageing. Many of the non-motor symptoms are common in ageing.
- decreased acuity
- “tired eyes”
- irritation (such as grittiness) or pain
- blurred or double vision
- visual-spatial confusion
- decreased reading
- decreased driving
- risk factor for dementia and visual hallucinations
- contributing factor in falls
Causes of visual impairment in PD:
- decreased blinking and dry eyes syndrome
- quality of tears is poor
- convergence insufficiency
- loss of retinal dopamine (causing loss of color discrimination and loss of visual contrast sensitivity)
- brain pathology of PD (causing visual-spatial impairment)
Subtle changes in vision are apparent in early PD. Is this a biomarker for early PD? (38:45) We could introduce neuroprotective drugs earlier.
Changes in retinal function progresses in parallel with PD. Is this a biomarker for disease progression?
Treatment of impaired vision:
- hydration (aqueous drops 4-5 times/day, viscous or gel preparations, increase humidity in house, punctal occlusion for severe cases)
- use of near vs. distance glasses
- dopaminergic medications can help vision (and vision may fluctuate along with these meds) (41:30)
Q&A with the Panel
Question: Any link between PD and pal optic nerves (sp?)?
Answer by Dr. Goudreau: The optic nerve fiber layer is not the one that seems to degenerate in PD. The interconnection cells are degenerated in PD.
Question: (56:40) Severe double vision.
Answer by Dr. Goudreau: With any of these non-motor symptoms, PD may not be the only explanation for them. Severe double vision can be due to PD. Need to see an ophthalmologist. This can be treated with prisms. Cover up one eye when reading. Alternate the patch.
Question: (14:36) How do you do an eye exam in someone who has difficulty communicating?
Answer by Dr. Goudreau: There are limits. But there are some basic parts of the exam that could probably still be done.
Question: (15:30) Impairment in visual-spatial processing.
Answer by Dr. Goudreau: Challenging area.