Hemianopsia - Vision Loss After A Stroke Or Brain Injury
This protocol is only to be used when Rx’d by an optometrist or when under the in-person supervision of an optometric physician, a physical therapist, or an occupational therapist.
The Care Of Hemianopsia And/Or Neglect
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 a hemianopsia are usually very aware of the side vision loss.
“Neglect” (also known as hemi-spatial inattention) is the inattention to, or lack of awareness of visual space to the right or left and is usually associated with a hemianopsia. The symptoms and signs of hemi-spatial 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.
These procedures are not in any particular order. it is up to the healthcare professional to decide the order, based on the patient's interest and/or ability.
- Train the patient to visually scan (pursuits and saccadics) monoculary in the direction of the field loss, but emphasize scanning with minimal head turning. When monocular scanning is performed well, then binocular scanning can be trained. After that, a head turn is acceptable as long as it always follows a visual scan.
- Perform eye movements in the direction of the field loss re-enforced with auditory input (snapping the fingers or use of a "clicker" or bell).
- Have the patient walk around the room in the direction of the affected side in order to create a visual-motor map of space on the neglected side.
- Have the patient use a flashlight aimed alternately toward each foot while walking, to enhance vision with visual-motor reinforcement on the affected side. At first, the flashlight is held by the hand which is not on the side of the field loss. Later on, the hand on the side of the neglect should be used.
- Encourage the playing of games like crossword puzzles and hard copy card playing (not computer games), but they must cross the midline toward the affected side.
- Increase sensory awareness on the affected side. Have the patient squeeze a ball on the side of the field defect and then have them scan visually in that direction to find the ball. Have the patient trace a line that extends toward and through the field defect. Place the patient's finger in the area of neglect, with the therapist rubbing the patient's finger to stimulate sensory awareness on that side, and then have the patient scan visually to find the finger.
- Tell the patient to forcibly/rapidly move it eyes as far toward the field loss while sensing the feeling of their eyes at the extreme gaze. Encourage the patient to become aware of the "feel" of their eyes when gazing toward that side.
- To encourage frequent visual scanning toward the hemianopsia repeat with eyes closed while walking, have the patient wear a "beeper-timer" wristwatch set to beep at intervals, as a reminder to scan regularly toward the field deficit.
- Teach patients with hemianopsia to visually scan about 20° toward the field loss, and only then to turn the head in the direction of the field loss. This prepares the patient for the scanning eye movements required when Side Vision Awareness Glasses are prescribed.
- Use therapies to stimulate visual and physical movement into the area of neglect, like balloon catching/tossing, and also searching for predictive (and later non-predictive) stimuli in the neglected field.
- Turning a page at a 45° angle will improve reading ability for some patients with hemispatial neglect who do not respond to other treatments.
- Enhancing the potential "blindsight" of hemianopsia will allow a patient more spatial awareness (at a subconscious level) within their hemianopic field defect.
Some patients with blindsight, after a while may be able to detect the orientation of a vertical or horizontal line, the color of a green or red object, and/or can point to the approximate location of a moving object held within the area of the field loss. "Blindsight" awareness training should be attempted with every hemianopic patient.
- Teach the patient to read. These unique reading guides are much more effective (and more professional) than a line drawn with a marker down the edge of the patients reading the material.
- Use "Hemianopsia Buttons" to instruct the patient's family to learn to sit on the side of the neglected field, in order to encourage the patient to attend to space on that side. The hemianopsia button is also worn by the patient in the OT/IDT treatment room, allowing busy therapists to be immediately aware of whether the patient they are treating has a right side or left side hemianopsia without having to refer to the chart.
- Have the patient sit in a chair with both feet flat on the floor. Spread a group of simple three dimensional shapes (i.e. Colored cubes or shape blocks) on a table in front of the patient within their physical reach.
- Depending on the patient's ability level, either verbally call out the color and/or the shape and have the patient touch the called out target. It is very important to encourage reaching and touching of the target in order to provide the motor stimulation that aids in the development of the visual motor map of space, to enhance the accuracy of saccadic and pursuit eye movements.
- Give the patient clues verbally and physically by waving your hand in the general location of the target if the patient is unable to locate to the target.
- Encourage the patient to visualize the full visual field.
- Encourage the patient to verbalize.
- To make the exercise more challenging, add a cognitive demand. While the patient is searching for the targets, have him/her do math problems or sell words.
- Perform the exercise timed and encourage increased speed.
- Decrease the motor component of reaching and touching as target localization improves
- Have the sit or stand about 10 feet in front of a large uncluttered wall. Spread a group of targets (can be memory game card pictures, playing cards, word flash cards, math problems, etc. based on the patient's performance and cognitive level) on the wall in front of the patient. Place more targets in the missing or neglected visual field, but make sure there are least a few targets in all fields.
- Have the patient hold a matching set of targets (memory card matches, corresponding suits of playing cards, or answers to math problems) in their hands.
- Have the patient turn up a card in their hand and then visually locate its match on the wall.
- Give the patient clues verbally and/or physically by waving your hand in the general location of the target if the patient is unable to locate the target.
- Encourage the patient to visualize the full visual field.
- Encourage the patient to verbalize.
- To make the exercise more challenging, add a cognitive demand. While the patient is searching for the targets, have him/her do math problems or spell words. Make sure cognitive demand does not deter significantly from visual scanning performance.
- Perform the exercise timed and encourage increased speed.
- Add forward and backward walking and/and or add a balance board or beam.
"Side Vision Awareness Eyeglasses" (SVAG)
Note: Please be in touch with your local low vision doctor as to how to obtain this device.
- For Right Hemianopsia Buttons, Order # AFR225R
- For Left Hemianopsia Buttons, Order # A=R225L
- For Reading Guide Set (for Right and Leit Hemianopsia), Order #ER049
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.
Once a patient has learned compensatory visual scanning in the direction of the hemianopsia, advanced optical technology prescription Side Vision Awareness Glasses (SVAG) should be considered for safer ambulation, and to enhance activities of daily living in the direction of the field loss.
Read What Some Patients Are Saying And Learn More About Side Vision Awareness Glasses
SVAG Bring The Objects Toward The Left Into My Vision
Most noteworthy has been spotting hanging traffic lights installed on the left-hand side of the street, bringing them into full view. Walking in rural or urban areas I am more aware of my surroundings and can better avoid bumping or tripping. On the lighter side when sitting in the passenger seat of the car, I am able to see the speedometer and monitor my husband's speed.
The Use Of SVAG Have Been Very Helpful When Shopping
The use of Side Vision Awareness Glasses have been very helpful when shopping, helping me to avoid items left by clerks on the floor. They also help me maneuver through obstacle courses of items such as carts or floor displays. Also while walking in the neighborhood, I can more easily watch for cars before crossing the street.
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.
SVAG Have Important Advantages
- SVAG have a high ABBE value, so they reduce distracting color aberrations seen through other lenses.
- They have a higher index of refraction, so SVAG is a thinner and more cosmetically acceptable lens, without an obvious line on the front of the lens, and without an unsightly thick button, or lens strip inserted through the front of the lens.
- Thanks to better contrast sensitivity than found with Fresnel-lens based glasses, SVAG provide improved vision.
- SVAG have the widest viewing area, allowing better field awareness in the direction of the hemianopsia than button lens systems. And because SVAG have a vertical edge, the person with hemianopsia just needs to move their eyes a couple of millimeters to get into the SVAG area of the lens, instead of having to travel past the curve of a button lens in order to find the widest possible viewing area.
- SVAG are easy for people to use because they don't superimpose a narrow peripheral image over a person's central vision (which is confusing and difficult to learn to use).
- SVAG are more attractive because the front of the lens is smooth. When the glasses are worn, the SVAG lens is barely noticeable.
- SVAG are less likely to accidentally break because there is no glued seam splitting through the lens from front to back as found in older attempts at field expansion.
Hemianopsia can leave people disoriented, insecure, and struggling to make it through the day. In addition, there are hemianopsia-related safety issues, such as bumping into furniture, walking into people at the mall, falling off a curb, and difficulty performing other activities of daily living. SVAG can give those with hemianopsia more freedom, independence, and safety. Using SVAG may even allow some of those with hemianopsia to return to driving (which may require special on-the-road testing and Motor Vehicle Department approval, depending on state law).
What To Include In A Possible Stroke Workup
History Of Stroke-Related Signs And Symptoms Best-Corrected Visual Acuity Pupil Reflexes
Cover test, phorias, ocular range of motion Threshold visual field testing Dilated fundus examination Stethoscope auscultation of the carotid arteries for bruits to resolve—an alternating eye patch may be the only treatment available.
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.
If there is ptosis, avoid disuse of the ptotic eye by taping it open about a centimeter for five minutes a few times per day using Transpore surgical tape. Be sure to allow enough slack in the tape for blinking. Patients should instill an artificial tear every minute to prevent discomfort and drying during the interval the eye is taped open.
If there is a blepharoparesis and the eye won't close, be sure to use Transpore surgical tape to keep the eye closed to prevent corneal staining and discomfort.
After years of watching physical therapists work use massage with stroke patients, I decided to try a similar massage technique on the eyelids. I found that some patients with stroke-related ptosis or blepharoparesis responded to an eyelid massage.
The massage is conducted with your finger, using a brisk moderate stroking of the affected lid in a lateral and radial fan shape. An alternating warm or cool pack applied before lid massages may increase sensory stimulation to the lids, enhancing the effect. Massage for a few minutes four times per day for three weeks. Discontinue if no change in ptosis or belpharoparesis.
Some ptosis patients have what I call diplopic pseudo-ptosis or DPP. Stroke survivors with a stroke-related esotropia or exotropia subconsciously learn to close the offending eye to avoid diplopia. Although they will appear to have ptosis, it is not ptosis. Cover the non-ptotic eye; if the patient is capable of opening the apparently ptotic eye, you have discovered a DPP.
For blepharoparesis, I sometimes use commercially available eyelid weights to pull the lid down. The lid weights come in a fitting set of graded weights with an adhesive backing. These test weights are used to determine the weight of a gold lid implant used by oculoplastic surgeons. Op tometrists can use the test set weights to treat blepharoparesis noninvasively until surgery is indicated.
Specialty optometric consultation is available through colleagues associated with Neuro-Optometric Rehabilitation Association (NORA) and the College of Optometrists in Vision Development (COVD).•