Contributed By Carol Pfeil
Eyesight is an astounding process. My eyes pick up light, and depending upon how close or far away the object is, the lens changes shape, shoots the image back to the retina, then the image of that object is sent via the optic nerve upside down to the brain where my brain flips it and gets the message that a cute, non-house-broken, 13 pound black and white Shih Tzu with a red bow, named Obi Wan, has just jumped onto my lap.
However, with PD’s breakdown in the production of dopamine in the mid-brain or gut, it is common to develop a number of eye movement difficulties. These problems may include dry eye due to a decreased blink rate with PD; eye movements that become slow or dysfunctional causing the eyes to not converge normally, or track. Visual hallucinations are also possible. Any one of these things, or all, can affect one’s ability to read, watch TV, or walk (which could warrant a fall) – that terrible 4 letter word.
We know that everyone’s PD manifests differently, and that includes eye movement issues as well. Most of us would agree that knowledge is power and concerns or problems are usually less frightening when discussed, named (if possible), and analyzed by an experienced medical professional. (Additionally, if I had a choice, I would choose one with a sense of humor.)
One such experienced and humorous physician, Dr. Scott Stevens, a Bend Ophthalmologist, recently taught us some anatomy-class-vocabulary and detailed some important information about PD’s effect on the eyes through a recent PRO webinar. (View the recording at youtube.com/user/ParkinsonsResources.) The very good news is that often a trip to an eye doctor can result in some very good solutions or at least accommodations for the problems. Some of these mitigators may include near or distance corrective glasses (or prisms added to glasses), walking assistance devices, or eye drops/ointments.
The most reported and common eye problem for those with PD is dry eye or Kerstoconjunctivitis Sicca. These challenges are often due to:
- A decreased blink rate (4-6 times a minute vs the non-PD 12-18 blinks per minute causes eyes to be drier)
- Blepharospasm (which causes abnormal and involuntary spasms of the eyelid resulting in eyelid closure),
- Apraxis of the eyelid opening (results in difficulty opening the eyes) and
- Blepharitis (inflammation of the eyelid margin)
These conditions are very common and are often eased with artificial tear eye drops or ointments. If you have tremor, the ointments may be your best bet. Other recommendations for dry eye treatment include applying a damp washcloth to the eyes and covering that with a gently microwaved seed infused sock (or other warmed pad) for a few minutes twice a day to increase eye moisture.
Other eye movement difficulties with PD are saccades (or eye movement). Saccade problems include:
- Inability to use both eyes at once to see or follow a moving object (Accommodative paresis or convergency insufficiency)
- Difficulty maintaining fixation on an object (impaired smooth pursuit)
- Slowed response to moving the eyes toward a new target (prolonged saccade latency)
- Eyesight undershooting a new target when your eyes move (hypometric saccades)
- Impaired ability to think and orient in different dimensions (visuospatial dysfunction)
- Difficulty moving the eyes back to a remembered target (impaired antisaccade)
This eye movement problem as a result of the saccades makes it difficult to read with both eyes working together for any extended period of time. It may also cause a person to experience balance issues, which can make the correction a tricky fix. Treatment may include single vision glasses for reading or changing the prism in the lens to mitigate the visual problems. Dr. Scott’s “simple” answer? Read with one eye – or try using a ruler to keep your place on the page, choosing large print books or an I-pad/e-reader for easier viewing.
Accommodations for the balance issues include distance glasses (not bifocals) and a cane or walker to maintain one’s posture, as not seeing in 3D often causes objects to look flat and navigating space can be problematic.
Lastly, it is common for those with PD to experience visual hallucinations, impaired color discrimination, and decreased contrast sensitivity.
With impaired color discrimination, colors may appear muted, but a person doesn’t usually test positive for color blindness.
With decreased contrast sensitivity, it’s difficult to see well in low light.
With impaired depth perception, things like steps may not be seen, resulting in falls.
With visual hallucinations, a person may see things that aren’t really there or experience double vision.
Because many of these symptoms related to color, contrast, depth, hallucinations, and double vision can exhibit similarly to a cataract condition, it can become difficult to know what’s caused by the PD and what’s unrelated. For those with PD experiencing these symptoms, creating special prisms in eye glasses can often allow someone to read more successfully.
The importance of a regular and thorough eye exam, along with discussion and evaluation by an Ophthalmologist, is important in increasing one’s quality of life with PD. At PRO, we believe that quality of life is always worth pursuing. Armed with knowledge, hope, and a little courage, keep moving forward and let us know how we can do to support you. Perhaps it doesn’t apply outside of the British political arena, but as the idiom says, “The eyes (ayes) have it. Salud!
Originally published in the July 2019 Parkinson’s Perspective
Learn more about Parkinson’s disease and the eyes by watching PRO’s webinar by Dr. Scott Steven’s. Find this topic and others when you visit our YouTube channel.