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Seeing Eye to Eye with Parkinson’s Disease

Guest Contributor: Dr. Jamie Ho, OD, FAAO, FCOVD

Visual deficits can appear in patients with Parkinson’s. These physical and functional disturbances can include changes to color vision, contrast sensitivity, eye teaming and complex visual processing.

The EYES are a window to the Brain

A standard eye health exam allows an optometrist or ophthalmologist to determine the health of both the outside of the eye and the inside of the eye. Dry eye syndrome which is an ocular surface disease can affect both the comfort and the quality of vision if left untreated. The retina and the optic nerve inside the eye are parts of the brain that can show signs of systemic disease (such as diabetes) and neurological brain conditions (such as multiple sclerosis) even before they are diagnosed. Detecting problems early can result in earlier intervention and better patient outcome.

Research suggests that the decrease in dopamine in Parkinson’s disease can impact retina function. Difficulties in the ability to discriminate between colors, or objects from a background under different lighting conditions (contrast sensitivity) can make daily activities hard to do. Poor contrast sensitivity makes it difficult for someone to get down stairs or see the ledge between the sidewalk and the road. Delays in the visual system’s ability to adjust to light makes it difficult to drive at dawn or dusk. Many people may find that they need to be more strategic with positioning lights to be able to read newspaper comfortably or even to get around their home safely at night.

Blurry or Double Vision?

Parkinson’s disease decreases the accuracy and speed of smooth eye tracking, eye jumping, and eye teaming. Difficulties in these eye movements can result in blur, intermittent double vision, poor depth perception, and visual disorientation. These functional problems can happen even if the visual acuity remains 20/20. Many of these problems are intermittent and may only be present during certain tasks, such as reading, or when the head is moving. Some patients may even feel emotionally insecure when they cannot judge the space between objects on the floor or feel they can navigate through busy environments safely.  There is definitely concern for an increased risk of falls.  

Vision is Complex 

The visual system integrates with our vestibular system in our ears to provide orientation and balance feedback, as our head and body are moving. Motion, sensitivity, dizziness, and disorientation can result when this system does not work properly. The visual system also provides much information to our brain for eye-hand, body posture, and visually guided body movements, such as boxing.

Use it or lose it

Research shows that the cognitive and motor degeneration associated with Parkinson’s disease can be slowed down with exercise. Avoiding a sedentary lifestyle and regularly engaging in movements that encourage balance and involve the coordination of both sides of the body can significantly improve outcome. 

Practicing ‘vision’ can reduce the inaccuracies of eye movement. Here is an example of saccades practice. A saccade is a quick eye-movement that shifts the gaze from one field to another. We use saccades hundreds of times per day every time we shift our gaze from one object to another. 

If I am sitting near a window, I can practice saccades from one corner of the window to the other. I can practice shifting my gaze side to side or up-and-down or along the diagonal corners. I can practice a set of 30 shifts to the beat of a metronome (visual-auditory). I can also add hand and or foot tapping to the same or opposite side of where my eyes are shifting (visual-body coordination).

Different types of eye movements are controlled by different centers in the brain. By moving the eyes, we are exercising different parts of the brain. Oculomotor or strategic eye movement rehabilitation therapy has been shown to improve visual function in those with traumatic brain injury. More than 50% of the surface of the brain is devoted to processing visual information.

Finding Your Eye-care Provider(s)

While yearly eye exams are recommended for everyone for preventative eye-care and to ensure ocular health, many Parkinson’s patients would additionally benefit from a functional vision evaluation.  To find a neuro-optometric rehabilitation optometrist near you, please use the provider search engine for College of Optometrist in Vision Development ( or Neuro-Optometric Rehabilitation Association (

Dr. Jamie Ho is an author, lecturer, and an optometrist specializing in low vision and neuro-rehabilitation. She is a dual fellow of the American Academy of Optometry and College of Optometrist in Vision Development. When not in the office, you can find Dr. Ho hanging out with her family, hiking, cooking, reading on the newest trends of biohacking and optimizing brain health.

Neuro-Rehabilitative Optometric Physician

Low Vision & Vision Rehabilitation Services

5714 A Edmondson Pike

Nashville TN 37211

T: 615.604.2949

F: 615.376.0083

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