Vision Perception Problems

Stroke survivors can experience a variety of vision perception problems, depending on where the stroke occurs.

The brain stem houses three pairs of nerves that control eye movement. If they are damaged and do not allow one or both eyes to move together, it can cause double vision and visual midline shift.

Perception problems result from brain stem damage and are called ocular motility impairments. For example, double vision is a result of when the eyes are not able to move into the correct position.

Damage to the cerebellum can impair the ability to coordinate looking in the same direction.

Both the brain stem and cerebellum play a role in sensation. Damage to these areas can lead to loss of feeling, which makes blinking difficult and causes blurry vision or visual neglect.

Types

Common perception problems:

Double vision is when a person sees double, or two of one thing. The clinical term for double vision is diplopia. There are several specific causes of double vision, which can vary the type of distortion.
Visual midline shift is a condition in which the center point in one's line of sight is perceived as having shifted either left, right, above or below reality. For example, when a person with no vision problems stares at the center of a dartboard, he or she would expect to see the bullseye at the midpoint. But someone who has had a brain stem or cerebellar stroke and is affected by visual midline shift might interpret the midpoint of her line of sight as being an inch to the right of the bullseye. As a result, that person can become dizzy and may tilt her body to the right in order to compensate for the visual disturbance.
Visual neglect, also called inattention, is a condition in which the field of vision is not impaired, but objects in a certain area are ignored. Symptoms include failure to observe objects within a field of vision. Visual neglect can cause a person to eat food from only one half of his plate or shave only half his face. Stroke survivors with visual neglect can often recover completely.
Other visual perception problems include depth and distance perception, color detection problems, dizziness, hallucinations and failure to recognize common objects, which is called agnosia.

Treatment

There are several treatments designed to correct perception problems. Different symptoms require different treatments and sometimes a customized treatment plan is needed. Always ask your healthcare professional about which treatments best fit your needs.

Here are some common treatments for perception problems:

Prisms: Prisms can correct many perception issues, including double vision, depth perception, visual neglect and visual midline shift. The type and positioning of the prism differs depending on the symptom. For instance, with double vision, the prism is positioned on a glass lens to redirect the gaze of the eye that is abnormally aligned. In cases of visual neglect, a person ignoring objects on the left side of his field of vision might use a prism that reflects objects on his left to the right side of his field of vision.
Therapy and training: Because many perception problems are caused by lack of muscle control, various exercises geared toward building up muscle control can be effective. Training and therapy can restore awareness to the neglected area within the field of vision.
Eye muscle surgery: Surgery for post-stroke vision problems is often not an option because the vision problems are not caused by a physical injury. However, in some cases, surgery can be used to correct double vision.
Eye patches: Eye patches can be effective and cost-efficient, but do not alleviate double vision permanently. Nevertheless, if therapy and treatment have proven unsuccessful, wearing an eye patch can be a permanent solution.

Management

Some vision perception problems will never completely go away or may take a long time to fully heal. Prism users may need to wear glasses as a permanent solution.

Contrast sensitivity, which can affect depth and distance perception and reading ability, can be controlled with sunglasses or other tinted filters. Orange and amber-colored tints have been proven most effective.

Consult with an optometrist, ophthalmologist or primary care provider for suggestions about specific vision problems and symptoms.

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Vision Perception Problems

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