Below is a list of vision problems that may occur due to stroke:
Hemianopsia - This occurs when the visual field is cut in one-half of each eye. The person with hemianopsia will not see objects on the side where the visual field has been lost. Visual field is lost in one side of both eyes. Symptoms of hemianopsia may include only eating half of the food on one's plate, drawing only one side of an object, not being able to read one side of a page, and not seeing objects off to one side of the body. Patients with hemianopsia can be taught to compensate for their visual field loss by scanning their eyes in the direction of the hemianopsia and turning their head so they will not miss seeing objects on the affected side. Treatments for hemianopsia include saccade training or scanning therapy, boundary marking, lens that expand the visual field, and vision restoration therapy.
Saccades are rapid eye movements such as occur when the eyes move from one point to another in the visual field. Your eyes are constantly moving and use saccadic eye movement to take in bits and pieces of an object to create a whole picture for the brain. Scanning therapy or saccade training teaches a patient to scan toward the side of their hemianopsia. Saccades are often too short and slow in the patient with hemianopsia, and the patient has to be taught to scan further and faster with the eyes.
Boundary marking involves using some type of marker such as a Post It note or colored mark at the beginning or end of a line of text. This allows a patient to scan for the marker to find the beginning or end of the text.
Special lens have been developed to expand the visual field of a person with hemianopsia. These lens include the EP Horizontal Lens, the Gottlieb Visual Field Awareness System, and the Chadwick Hemianopsia Lens.
Visual Restoration Therapy is a computer-based treatment that attempts to stimulate existing visual neurons to rewire and make new connections. It is based on the premise of neuroplasticity. Some controversy has surrounded this technique, but it is approved by the FDA.
Visual Neglect - One will ignore objects off to one side of the body. Patients with visual field neglect often keep their head turned toward the non-affected side and rarely look over to the affected side. Helpful techniques for neglect include approaching and talking to the stroke victim from the affected side and encouraging scanning to that side. Teaching a stroke victim with neglect to scan to the affected side is more difficult than if they only have hemianopsia.
Diplopia - Double vision occurs causing a person to see two images of a single object. Some treatment techniques include vision exercises, prisms, and occlusion (patching one eye or part of the lens).
Dry Eyes - The stroke patient may have a slowing of the blinking rate or an incomplete blink which leads to the eyes drying out. Artificial tears and reminding the patient to blink fully may be helpful for this condition.
Sensitivity to Light - The eyes may have difficulty adjusting to different light levels. Sunglasses or tinted glasses may be helpful for this type of vision problem.
Convergence Insufficiency - With this eye disorder, the eyes do not turn in together (or converge) as they should when a person is looking at an object in midline near the face. You can test for convergence insufficiency by having a patient watch a pen as you move it toward their nose. In a normal response, both eyes should move inward as the pen moves closer to the face. Incoordination of the eye muscles due to stroke can lead to an abnormal response where one (or both) eyes do not move inward often causing double vision.