It is very common for people living with Parkinson’s to experience issues with their vision. A recent study found that 82% of people with Parkinson’s experienced one or more visual symptoms. These may include double vision, dry eyes, blurry vision, and sometimes hallucinations.
Fortunately, many of these symptoms are treatable or can be managed with proper care.
Here is an overview of causes, symptoms, and treatments for visual problems in Parkinson’s disease.
Causes of Vision Issues
Deterioration in vision is a natural side effect of aging. Diseases such as age-related macular degeneration, glaucoma, and cataracts become more common the older we get and may contribute tovision issues in people with Parkinson’s disease.
However, there are also vision issues attached explicitly to Parkinson’s disease. Like Parkinson’s, vision is connected directly to the brain and impacted by the neurotransmitter dopamine.
A significant portion of the brain consists of pathways that bridge the gap between the eyes and the visual areas of the brain, making it possible to process information such as color, shape, size, and motion.
Parkinson’s may impact the visual processing that facilitates this transfer of data, leading to many of the common eye issues seen in people with PD.
For example, Parkinson’s disease may cause a loss in retinal cells in the eye that utilize dopamine to perceive color. This can reduce the ability to sense colors or make them appear duller. Additionally, Parkinson’s can impact the eyelids, causing people with PD to blink less frequently or more rapidly.
Understanding Eye Movement
To understand how PD impacts the eyes, it’s helpful to know the primary types of eye movement:
- Pursuit Eye Movement: Allows both eyes to work in tandem to follow a moving object horizontally and vertically.
- Saccadic Eye Movement: Rapid eye movement that allows eyes to jump quickly between targets, such as when skipping to a new line while reading.
- Vergence Eye Movement: Allows the eyes to work together to adjust to a target when it moves towards or away from a person.
Parkinson’s disease can impact these eye movements in a few specific ways. For example, saccadic movement may be slower in people with PD, making reading difficult. Similarly, the eyes may experience issues working in tandem when a target is coming toward a person, causing double vision.
Common Vision Issues for People with PD
Only some people with Parkinson’s disease will experience vision issues, but for those that do, these symptoms can significantly impact comfort and quality of life. Here are the most common vision issues experienced by people with Parkinson’s.
Dry eyes are a result of decreased blinking and, in some cases, medication. Despite its names, dry eyes are not limited to the sensation of dryness and may include other side effects such as blurred vision, increased glare, or light sensitivity. Soreness, stinging, itching, or redness may also accompany dry eyes.
Over-the-counter eyedrops or artificial tears help to treat dry eyes. There are both daytime and nighttime eye drops, which provide more lubrication since eyes tend to dry out during sleep.
Ask your doctor about prescription eyedrops or procedures that may help to boost lubrication. If you experience eyelid inflammation, known as blepharitis, a warm compress can also help to ease irritation.
As mentioned above, double vision may result from issues with vergence eye movement in people with PD. Double vision is characterized by seeing two of the same thing and may also be associated with dry eyes or cataracts. Deep Brain Stimulation (DBS) may also worsen the condition.
There are several ways to treat double vision, most involving specific lenses. A special type of eyeglass called a prism may alleviate double vision. A doctor may also prescribe two separate glasses – one for reading, and one for far distances, to relieve symptoms. Wearing an eye patch can also help resolve double vision.
Impaired Depth Perception
Depth perception is the ability to process where things are in space. Issues with depth perception may stem from impairment in one eye due to cataracts or other vision loss. Depth perception may present a challenge to people with PD by triggering freezing – a sensation that your feet are stuck to the floor – and can impact daily activities, including the ability to drive.
Unfortunately, no medications or treatments specifically address depth perception issues, but certain tactics help to manage symptoms. These include incorporating good lighting, especially during evening activities, and utilizing devices that aid in visual cues.
Visual hallucinations can be distressing, and roughly half of people with Parkinson’s experience them. These may consist of movement in the peripheral vision or the sense of a fleeting shadow or passing shape.
Hallucinations are caused by an imbalance of visual information between images and memories stored in the brain and input from the outside world, causing people with PD to see things that aren’t there. Hallucinations can also be a side effect of certain medications.
You should discuss hallucinations with a movement disorder specialist or your doctor, no matter how mild. A professional can help adjust your medication or pursue more targeted treatment.
Prioritizing Eye Health
The best way to stay ahead of vision issues is to schedule regular exams with an eye physician. A standard eye exam includes a series of tests that measure visual acuity, depth perception, eye alignment, and eye movement.
Eye health is especially important for people with Parkinson’s. Not only is a significant percentage of vision loss preventable, but it can also disproportionately impact people with PD by increasing the likelihood of falls, fractures, mental health issues, and dementia.
An optometrist, ophthalmologist, or neuro-ophthalmologist can help diagnose PD-related vision issues and assign treatment as necessary.
While vision issues are common in PD, they are often preventable or treatable. Be sure to consult with your doctor or eye physician about how to stay on top of vision health and keep them in the know on any of the signs or symptoms you may experience.
For more on vision issues in PD, check out our Let’s Talk Parkinson’s feature on “Understanding Eye Issues in Parkinson’s” with Alexander M. Solomon, MD.