Vision After a Stroke or Brain Injury

The Care of Hemianopsia And/Or Neglect – Vision After a Stroke/Brain Injury
Patients who have had a stroke or traumatic brain injury may lose one-half of their side vision to the right or left. This is called “hemianopsia”. Patients who have hemianopsia are usually very aware of side vision loss.

“Neglect” (also known as hemispatial inattention) is the inattention to, or lack of awareness of visual space to the right or left and is usually associated with hemianopsia. The symptoms and signs of hemispatial inattention are:

  • The patient cannot or does not, readily or spontaneously scan into the area of the hemianopsia.
  • The patient doesn’t have a conscious awareness of the existence of their field loss.
  • The patient consistently bumps into things on the side of the hemianopsia.
  • When reading, the patient misses parts of words on the side of field defect and/or during a visual acuity test, misses letters on the eye chart on that side.
  • The patient postures with a head or body orientation away from the side vision loss.

Hemianopsia Is One Of The Most Common Side Effects
Hemianopsia is one of the most common side effects of a stroke or traumatic brain injury. It can leave the patient disoriented and struggling just to make it through their day. Patients can find themselves afraid to go out, concerned about their safety. If you’re suffering from side vision loss or someone who cares for such a person, let your doctor know about SVAG (Side Vision Awareness Eyeglasses ).

Stroke-Related Hemianopsia Is Reasonably Common…
Stroke-related hemianopsia is reasonably common. The field defect is obvious on a 24-2 threshold visual field test.

However, some stroke survivors have hemi-spatial inattention (also known as “neglect”), which is an inattention to or lack of sensory awareness of visual space to one side. It may or may not be associ­ated with a hemianopsia.

Patients with hemi-spatial inattention will usually be unaware of their inabil­ity to perceive space on the affected side, may not be able to follow a moving target in the direction of the neglect, and may say that their physician or occupational therapist “said” that they have visual con­cerns to the side (although the patient is not cognitively aware of the hemiano­pic like loss of visual field). That is a difficult concern to address and should be referred to an optometrist skilled in neuro- optometric rehabilitation.

Hemianopsia usually leaves a person disoriented and struggling to make it through daily living. People with hemi­anopsia are often afraid to leave their homes and are concerned about their safety. They are confused in a busy visual environment—such as the mall where they may bump into people—or have the fear of falling off a curb.

Hemianopsia can cause a sense of loss of independence due to discontinuing driving. Others find that ambulatory ac­tivities are more difficult. People with hemianopsia (but without hemi-spatial inattention) can often be helped by an optometrist.

As a minimum, recommend two sepa­rate pairs of glasses: one for distance and one for near. Separate pairs are needed because with hemianopsia, bifocals or progressive lenses limit the width of the seeing area through the glasses. In my experience, hemianopsia patients usually have fewer field-related complaints with full-field single-vision glasses.

I have prescribed specially-designed eyeglasses over the past 20 years to help those with hemianopsia. The optical care of hemianopsia is based on using prism to expand side vision awareness. Avail­able hemianopsia-related glasses I worked with were difficult to prescribe, difficult for the patient to use, or had optical de­sign flaws.

I learned what worked and what didn’t work. I designed a prism technology called SVAG (Side Vision Awareness Glasses) that can be prescribed by any trained optometrist (See Figures 1 and 2).

Prior to developing SVAG, hemianopsia­related eyeglasses afforded only a limited circular viewing area. This limited the patients’ appreciation of the expanded field awareness or required a highly-cog­nitive patient who could adjust to simul­taneously viewing straight ahead while noticing out-of-focus peripheral images caused by Fresnel prism.

I developed SVAG with a high Abbe value because patients with older hemi­anopsia glasses complained of distract­ing color aberrations. SVAG also have a higher index of refraction, making them thinner and more cosmetically accept­able. There is also no prism button or Fresnel lens strip on the front of the lens. SVAG provides clear side vision with a wide viewing area when looking through the prism lens.