3 Common Misconceptions About Neurological Vision Impairment
Changes in vision are one of the most common symptoms in those with brain injuries and neurological diseases. In fact, it’s estimated that up to 90 percent of those with brain injuries experience some type of visual change.1 Despite this, many rehab therapists feel unprepared to address how changes in vision impact daily function.
To help you improve your patients’ outcomes, let’s address three of the most common misconceptions about diplopia (double vision), cortical vision impairment (CVI) in adults, and vision impairment in Parkinson’s disease (PD).
Misconception #1: Pirate Patching Is the Best Way To Compensate for Double Vision
Patients with brain injuries can experience diplopia, also called double vision. Often this occurs from changes to function in cranial nerves 3, 4, or 6, which can lead to a strabismus, an abnormal misalignment of the eyes. Although most diplopia resolves within six months of the injury, patients still need to live their lives in the interim. Diplopia isn’t just annoying; it can cause fatigue and headaches as well as limit a patient’s ability to complete daily activities or participate in therapy.
Many clinicians use full occlusion—or a “pirate patch”—to manage these symptoms. Full occlusion can cause an increase in falls, discomfort, poor tolerance to activity, and reluctance from clients, as it alters their appearance and creates monocular vision. Partial occlusion is quick and easy to apply and has many advantages when compared to full occlusion.
In partial occlusion, opaque tape is applied to the glasses lens of the non-dominant eye. A small amount of tape is applied unilaterally to block the misaligned binocular input. This is typically better tolerated than full occlusion because it allows the client to use their dominant eye during vision-based activities, which reduces fatigue and headaches. The opaque tape allows light to enter the eye. It does NOT require a rotating taping schedule and allows your client to use their peripheral vision and improves depth perception during activities, which may prevent falls. This approach, paired with other environmental modifications, can increase your patient’s ability to participate in daily activities until their symptoms resolve or they can seek care from a specialized vision care provider. Remember: As with all interventions, it is up to the therapist to determine if partial occlusion falls within their scope of practice and to request the appropriate orders from the referring physician prior to initiating.
Ready to learn more? Watch Treating Oculomotor Deficits in the High-Acuity Adult Client.
Misconception #2: Cortical Visual Impairment Only Impacts Children
Cortical visual impairment (CVI), also called cortical blindness, is a form of vision loss that occurs when the primary visual cortex or visual pathways of the brain are damaged, yet the structures of the anterior eye are intact. Changes in visual processing can cause impairment in daily activities, including reading, functional mobility, driving, and object identification. Current evidence on CVI is almost exclusively on children; however, CVI does occur in adults with brain injuries and is especially common in those with anoxic or hypoxic brain injuries. Recognition and diagnosis of CVI in adults is complicated, as brain imaging may only have subtle findings and clients are often unable to self-report due to changes in cognitive or language abilities.
Adults with CVI have fewer symptoms than children as their visual system is fully developed before injury. Adults typically experience visual field preferences and/or unilateral spatial neglect, visual field deficits, difficulty with visual complexity, and difficulty with visually guided reach. Patients with CVI benefit from an approach that considers their specific needs. Simple strategies such as reducing visual clutter, using a typoscope, adding contrast, and optimizing lighting can improve outcomes.
Ready to learn more? Watch Demystifying Complex Brain-Based Vision Impairment.
Misconception #3: Parkinson’s Disease Has Limited Impact on Vision
Many clinicians are aware that Parkinson’s disease (PD) impacts the availability of dopamine in the brain, but did you know that dopamine is also essential in the eyes? Retinal dopamine levels impact light-to-dark adaptation, color vision, visual acuity, changes in eye movements, and pupillary reactivity. Those with PD can also experience a slowed blink rate, peripheral field loss, and visual hallucinations. Despite these many changes, patients frequently underreport vision changes unless they are asked pointed questions. These changes can limit a patient’s ability to use vision to compensate for motor deficits.
Increased awareness of the impact to the visual system for those with PD is necessary to optimize interdisciplinary outcomes and to ensure that patients receive appropriate referrals. Quick and easy strategies such as mitigating variations in home lighting can help prevent falls and increase independence.
Ready to learn more? Watch Vision Deficits: Parkinson’s Disease, Dementia, and Multiple Sclerosis.
Better Identify and Treat Functional Vision Deficits from Neurological Changes
The eye is often considered the window to the brain. Enhance your knowledge of best practices in the identification and treatment of functional vision deficits from neurological changes by watching our full series of courses, starting with Visual Field Deficits and Neglect: Impact on Daily Performance. These courses address common vision impairments in those with PD, Alzheimer’s disease, and multiple sclerosis along with symptoms of neurological vision changes, including oculomotor deficits, CVI, visual field deficits, and unilateral spatial neglect.
References
- Ciuffreda, K. J., Kapoor, N., Rutner, D., Suchoff, I. B., Han, M. E., & Craig, S. (2007). Occurrence of oculomotor dysfunctions in acquired brain injury: a retrospective analysis. Optometry (St. Louis, Mo.), 78(4), 155–161.
