People living with Parkinson’s Disease (PD) can have functional impacts in many facets of their day, ranging from mobility, self-care, sleep and many more. PD affects many parts of an individual in both motor and non-motor capacities.
Recently, researchers have begun to study in the impact that PD has on one of the lesser known symptoms, vision. Although the impacts on vision is just now beginning to touch the surface, what researchers do know, is that in as many as 75% of PD patients report at least one visual symptom related to PD such as reports of dry eyes, , visual fatigue, blurred vision, double vision or depth perception changes(7). In fact, now researcher is showing that one of the earliest symptoms of PD can actually be changes to vision(4).
One of those earlier changes is what is known as changes to contrast sensitivity (4). Contrast sensitivity is related to our ability to detect objects in our visual field and be able to tell the foreground from the background (7). An example of this is the picture of these carpeted stairs to the right. Since these stairs are all of similar color, there is not much contrast between one-step to the other. This low contrast between steps can make it difficult to tell where one step ends and the next step begins. Another example is in this chart to below, as the chart decreases in contrast sensitivity as it progresses down the page. Visual acuity is normal and maintained throughout the page, but the ability to read the page becomes more difficult because the sensitivity has changed.
Symptoms of Contrast Sensitivity Changes
Understanding the impact of contrast sensitivity in PD is important as research shows that many PD symptoms can be predicted by this progressive change(7). Specifically, in PD, difficulties with contrast sensitivity and visual changes can be related (4 & 7):
- Freezing of gait and gait impairment
- Difficulty with reading
- Visual hallucination
- Misjudging objects and distances
- Difficulty with dressing
- Driving, especially at night or in foggy conditions
How To Manage Impaired Contrast
Although there is no quick fix for improving contrast sensitivity, there are some things that can be done to your environment to compensate for these changes. First, some studies so that contrast sensitivity can be partially improved by L-DOPA (7). For this reason, it is important to mention all vision changes, no matter how small, to your physicians and rehabilitation team, as this might be an important factor in determining plan of care. Additionally, exploring ways to increase in your environment can be helpful, such as using adaptive equipment or trying low vision glasses.
Lastly, work with your local services to discuss these vision changes in order to find resources and supports to ensure safety and success at home.
Access the free guide from AOTA for home safety tips when living with vision changes.
The Florida Division of Blind Services helps blind and visually impaired individuals achieve their goals and live their lives with as much independence and self-direction as possible.
The Independence with Low Vision Program, in partnership with the Florida Division of Blind Services, provides training for adults and seniors who have experienced severe vision loss or blindness to enable them to continue to live safely and independently in their homes, travel safely in the community and improve their quality of life.
Occupational Therapists (OT) and Certifies Low Vision Therapists (CLVT) are available across the country to help individuals living with vision changes. Reach out to your local physician for referral information.
Pictures & References
- BBTO Guided Reading Strips Colored Overlays Highlight Bookmarks for Reading [Online Image]. (n.d.). Amazon.com. https://www.amazon.com/BBTO-Reading-Overlays-Highlight-Bookmarks/dp/B07KM2BDKX
- Cars Driving on a Rainy Day [Online Image]. (n.d.). Goodfreephotos. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.goodfreephotos.com%2FFree-Stock-Photos%2Fcars-driving-on-a-rainy-day.jpg.php&psig=AOvVaw1ZyIYNRBAfAd263KEHOpMO&ust=1600293004818000&source=images&cd=vfe&ved=0CAkQjhxqFwoTCPiAlJeS7OsCFQAAAAAdAAAAABAD
- Cocoons L Pilot OveRx Sunwear-Black Fr-Yellow Lens [Online Image]. (n.d.) MaxiAides.com. https://www.maxiaids.com/cocoons-l-pilot-overx-sunwear-black-fr-yellow-lens
- Guo, L., Normando, E., Shah, P., Groef, L. & Cordeiro, MF. (2018). Oculo-visual abnormalities in Parkinson’s disease: Possible value as biomarkers. Movement Disorders, 33(9): DOI: 10.1002/mds.27454
- Heiting, G. (n.d.) Contrast Sensitivity Testing [Online Image]. https://www.allaboutvision.com/eye-exam/contrast-sensitivity.htm
- [Untitled illustration of stairwell]. (n.d.). Rehabilitation Research Design & Disability. http://www.r2d2.uwm.edu/cds2/shrp-gallery/stairs-desc.html
- Weil, R. S., Schrag, A. E., Warren, J. D., Crutch, S. J., Lees, A. J., & Morris, H. R. (2016). Visual dysfunction in Parkinson’s disease. Brain : a journal of neurology, 139(11), 2827–2843. https://doi.org/10.1093/brain/aww175
- What the Crutch? Tips and Stories About my Friends! [Online Photo]. (31, August 2013). https://supinemusings.wordpress.com/2013/08/31/what-the-crutch-tips-and-stories-about-my-friends/.