Optimizing Vision in Parkinson’s Disease

Vision is a capability that most of us take for granted.  Did you know that ⅔ of the brain’s mass is dedicated to processing visual information?!  Take a second and think about it… What activities do you do on a regular basis that don’t involve your vision?  (Sleeping is about the only one I can think of!) 

How does vision specifically relate to Parkinson’s Disease?

  • More than 75% of people with PD report experiencing at least one visual symptom!

  • Dopamine is present in the visual system!  Some cells within the retina use Dopamine to communicate.  Therefore, the general lack of Dopamine associated with PD may contribute to visual complaints and symptoms.

  • The eyes are muscles too!  If you exercise the rest of your body, why not your eyes?  Just like any other muscle, the eyes require range of motion or movement for scanning the environment, motor control, and coordination.

  • Visual deficits alone are strongly associated with postural instability.  For those with PD and balance impairments, visual input is relied on even more heavily for stability.  If balance and vision are both impaired, then postural instability is affected even more, and thus the risk for falls is also greater!

 

Visual symptoms in Parkinson’s Disease

  • Central and color vision abnormalities – may be described as:

    • Blurred vision

    • Colors appear “washed out” and less vibrant

    • Difficulty seeing in twilight hours or when raining

  • Ocular surface irritation – caused by poor tear production and reduced blinking response as a result of PD, with symptoms including:

    • Dry eyes

    • Irritation (gritty / sandy sensation)

    • Burning

    • Redness

    • Crusting on the lashes

    • Eyes “stuck shut” in the mornings

    • Sensitivity to light

  • Decreased contrast sensitivity or decreased ability to detect subtle differences in shading and patterns – for example:

    • Difficulty seeing in dim lighting

    • Difficulty discerning where one step starts and one step ends when ascending or descending stairs

  • Diplopia or double vision

  • Convergence insufficiency or decreased ability to adduct (“cross”) the eyes and maintain fusion/alignment of the eyes while focusing on a near target, often described as experiencing the following symptoms:

    • Blurred or double vision

    • Headaches

    • Eye strain

    • Difficulty reading

  • Impaired visual processing

    • Impaired depth perception (most common complaint!)

    • Impaired object perception, such as difficulty identifying overlapping objects and/or impairment in mental ability to rotate objects

    • Impaired visuospatial construction, in which copying and recalling complex figures becomes difficult

    • Impaired motion perception, with difficulty accurately judging the direction and/or speed of a moving object

    • Impaired face and emotion recognition

  • Peripheral vision deficits  – as compared to other disorders, these deficits may present as distractibility by visual information in the periphery rather than loss of peripheral vision

  • Visual hallucinations

  • Blepharospasm or the forceful contraction of the eyelid

  • Apraxia of eyelid opening or impaired motor command to open the eyes

  • Vertical eye movement limitations

Each of these visual abnormalities alone are typically mild and subtle, but when they occur in combination (especially in conjunction with balance deficits), the functional impact can be significant.

What should I do now to optimize my visual skills?

  1. Maintain routine annual ocular health and acuity assessment with your optometrist and/or ophthalmologist

    • Ensure your eyeglasses or contact lenses are corrected for your best possible acuity

    • Treat ocular surface issues to protect the eyes and optimize visual clarity

  2. Keep your primary care physician, neurologist, and/or movement disorder specialist updated on any visual changes or new symptoms

  3. If visual changes or symptoms are present, consider a referral to a neuro-ophthalmologist

  4. Request a script from your physician for occupational therapy 

 

Remember, the earlier these visual symptoms (or any PD symptoms for that matter!) are identified and treated, the greater the improvement in quality of life!

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Parkinson’s and Walking