On November 13th, the American Parkinson Disease Association (APDA) hosted a webinar on the effects Parkinson’s has on vision- fun fact: did you know that dopamine plays a role in your retinas as well as your brain? The webinar was hosted by Jennifer Gillick, the program director of the Northwest chapter of the APDA, and the special guest was Dr. Steven Hamilton. After Dr. Hamilton presented an informative overview of PD’s effects on vision, Jennifer relayed to him questions from the audience.
Neuro-ophthalmology is a subspecialty of both neurology (study/treatment of nervous system disorders) and ophthalmology (study/treatment of eye disorders) and requires expertise on problems of the eye, brain, nerves, and muscles. Dr. Hamilton practices at Swedish Neuroscience Institute, at Swedish Medical Center in Seattle, Washington.
For a summary of the talk, see my notes below.
– Cassandra Irizarry
The Impact of PD on Vision
November 13th, 2020
Webinar hosted by the Northwest Chapter of the American Parkinson Disease Association (APDA)
Speaker: Dr. Steven Hamilton, neuro-ophthalmologist
Summary by Cassandra Irizarry, Stanford Parkinson’s Community Outreach
Dr. Hamilton: Doctors often say there’s not much that can be done about vision problems related to Parkinson’s and can be unaware of how PD can affect vision. I’m going to rely on you to pass this information to your own eye care providers.
Visual Complaints in PD
- 75% of PD patients have oculomotor signs (eye movement)
- Michael J Fox Foundation is funding research into this
- 75% experience blepharitis (low-grade inflammation of the eyelids)
- two-thirds have dry eyes (results in blurry vision)
- 25% report hallucinations (sometimes a side effect of medication but not always)
- Other common symptoms:
- Blurred vision, double vision, light sensitivity, eye strain, reading difficulties
Dopamine in the Eye
- Dopamine is present in the retina of your eye, as well as the visual cortex
- Problem: the role of dopamine in the retina is unclear
- Primary sites of pathology:
- Loss of dopamine cells in substantia nigra compacta of midbrain and putamen
- Secondary sites:
- Dopamine depletion in the visual cortex and retina
Pareses of gaze (abnormal/slowness of eye movements)
Accommodation paresis (paralysis; impairment of focusing)
Reflex blepharospasm and blepharoplegia (involuntary excessive blinking; not being able to open eyes)
Keratitis sicca (dry eye syndrome)
No hemianopia (no loss of visual field)
Sensory abnormalities (visual hallucinations)
Oculogyric crises (when eyes get stuck in an upwards gaze; usually side effect of medication)
No nystagmus (nystagmus: inability to hold the eye still)
Pareses of gaze
- Slow eye movements with incomplete upgaze
- Jerkiness; “cogwheel” visual pursuit of moving objects
- Ex: when you follow a plane in the sky with your eyes, that’s smooth pursuit. A PD patient wouldn’t smoothly follow it
- L-dopa improves slow eye movements and incomplete movements
- Can make it difficult to read
- Impaired focusing at near results in double vision and reading problems
- May result in anticholinergic medications for tremor (Atrane, Cogentin, Benadryl)
- Convergence insufficiency causes double vision or eye strain
Reflex blepharospasm and blepharoplegia
- Inability to open the eyes due to:
- Blepharospasm (excessive blinking)
- Apraxia of eyelid opening (not being able to initiate opening of the eye)
- Avoidance of double vision
- Results in eye pain and blurred vision
- Multiple factors include:
- Infrequent blinking
- Seborrheic dermatitis (can be treated with creams)
- Decreased treats from medications and autonomic dysfunction
- PD blink rate may be 1-2 blinks per minute (people without PD: 16-18 blinks per minute)
- Creates expressionless stare
- Complicates management of dry eye syndrome
- Hemianopia: when an eye is missing half of the visual field
- No visual field defects in PD except post-pallidotomy
- Early pallidotomy patients had a 40% incidence of homonymous hemianopia
- Modern pallidotomy results in 5-10% of superior quadrantanopia
- Impaired contrast sensitivity common
- Poor color discrimination in the blue/yellow axis
- Hallucinations in 25-40% of patients
- Usually older patients with poor vision who are on medications
- Patients with this symptom would benefit from increasing the contrast on their TV and/or computer
- Common with post-encephalitic PD
- A side effect of neuroleptic drugs
- Painful, forced, and upward turning of both eyes
- Nystagmus is not seen in idiopathic PD
- Myerson’s sign:
- Failure of the blink reflex
- Wilson’s sign:
- The need to blink to change the direction of gaze
- Hypermetric saccades (eye movements), jerky smooth pursuit with catch-up saccades
Management of Eye Problems
- Review the history of eye complaints
- Time spent reading? Are they able to read? Is vision double or blurry?
- Computer usage?
- Medication on/off effects?
- Use of anticholinergics or antidepressants (for the treatment of dry eyes and hallucinations, respectively)?
- Eyeglasses issues:
- Refraction with headrest or trial frame
- Use spherical equivalent for astigmatism
- Separate glasses for near, intermediate, and distance viewing
- IDEALLY NO BIFOCALS OR TRIFOCALS
- Try to avoid progressive lenses
- Blepharospasm and apraxia
- Can be treated with Botox injection
- Lid-scrubbing pads
- Non-preserved artificial tears
- Punctal plugs for abnormal Schirmer’s test
Reading Tricks in PD
- Use your finger as a placeholder
- Use a music stand or cookbook holder so hand tremors won’t interfere
- Use large fonts on the computer
- Many of the abnormalities of vision with PD can be addressed and improved
- Preservation of sight
- Is crucial to maintaining the dignity and integrity of the PD patient
- PD patients should find an empathetic and patient eye care provider
Question and Answer Session
Jen Gillick: Do you have any recommendations for cataract surgery for people with PD?
Dr. Hamilton: Cataract surgery is now typically now done with topical anesthetic drops that numb the eye, as opposed to local or general anesthesia. The procedure only lasts 20 minutes or so- the main concern is if the person can hold still. You’d want to have that conversation with your ophthalmologist about whether or not they’re worried about you moving around during the procedure. But PD doesn’t mean you can’t get cataract surgery- there are workarounds. My advice, after working with a lot of PD patients, would be to avoid the multifocal lenses, correct both eyes for distance, and then wear reading glasses.
What do you think of prisms in bifocals?
The problem for PD patients is that sometimes you need a prism for distance vs near and if you wear a bifocal, you might need one prism for the top part and another for the bottom. It depends on the alignment issue for your eyes- it might work for some, but not for others.
Do eBooks make reading more difficult than reading a hard copy book?
I think one of the issues is contrast impairment- what my patients have told me is that there are eBook settings to increase contrast, or even change it from black-on-white to white-on-black. Reading ideally should be one of those options.
Is there a relationship between PD and glaucoma?
No, not to my knowledge.
What drugs are likely to cause hallucinations?
Is double vision at longer distances vs close up vision a common problem with PD?
It’s usually more common up close than with distance, but can be either. It’s important to tell your doctor what kind of double vision you’re having. True double vision is an eye alignment problem that can be treated using prisms
If you’ve been using prisms for a long time, will you eventually have to get stronger ones?
As people age, often the prism needs to be strengthened- maybe every 2-5 years.
Are there specific recommendations you have for eye drops for dry eyes? What do you use for eye scrubbing?
When I was in training, we were taught to take a q-tip, put it under warm water, put a drop of baby shampoo on it, and then rinse out most of the soap before lightly scrubbing the lashes. Use a warm washcloth on the eyes before doing this, and be sure to rinse afterward. Baby shampoo can be irritating- you can get a product called “Avenova” from your eye care provider. It’s a spray- I use it myself on my q-tip. There’s another product called “We Love Eyes,” which can be bought online and has tea tree oil in it and some vitamin C. You can use the one that’s for eyelashes. I would use one of those 2 over baby shampoo, but lots of people use baby shampoo without a problem.
Is there vision therapy people with PD can do?
This works well with kids, but may or may not work well with people with PD, because it’s a brain, not muscle disorder. I think it’s easier to use prisms over visual therapy.
Is there a relationship between PD and macular degeneration?
No, not to my knowledge.
Are there specific PD medications that carry more eye-related side effects?
The ones that can cause visual hallucinations would be key to be aware of as well as the ones that have “anticholinergic side effects.”