Losing half your vision after a stroke or brain injury is more than just a diagnosis on paper. It can make everyday activities more difficult, like navigating a crowded store, noticing a person approaching from the side, or even just walking through a doorway. For people struggling with side vision loss, finding ways to adapt is incredibly important, and one option that can help is Side Vision Awareness Glasses. In this article, we discuss what these specialized lenses are and answer some frequently asked questions.
What Are Side Vision Awareness Glasses?
Side Vision Awareness Glasses®, or SVAGs, were developed by Dr. Errol Rummel of Jackson, NJ, after years of treating people with stroke-related, or brain injury-related hemianopsia. Hemianopsia is the clinical term for the loss of half the width of your field of vision; it is one of the most common side effects of a stroke or traumatic brain injury.
Side Vision Awareness Glasses are specialized low vision glasses that use built-in prism technology to expand the field of vision for patients with peripheral vision loss.
There are multiple benefits of SVAGs, including:
- A wide viewing area, allowing better field awareness. And because SVAGs have a vertical edge, a patient just needs to move their eyes a couple of millimeters to get into the SVAG area of the lens.
- A discreet appearance because the front of the lens is smooth, making the area with prism barely noticeable.
- A higher index of refraction. SVAGs are thinner, lighter, and more comfortable than other types of hemianopsia glasses.
The goal is not to make the blind area disappear; it is to improve awareness, navigation, safety, and confidence using the vision that remains.
Who is a Candidate for SVAGs?
A potential candidate commonly has:
- Stable right- or left-sided visual-field loss.
- Enough intact vision to recognize information redirected by the prism.
- Difficulty detecting people, doorways, carts, furniture, curbs, or other objects on the affected side.
- Sufficient attention and cognitive ability to learn how the shifted image should be interpreted.
- A realistic functional goal and willingness to practice.
Patients with significant visual neglect, uncontrolled diplopia, severe cognitive impairment, or difficulty understanding the prism image may have more trouble using the system. Hemianopia and visual neglect are not the same condition, although they can occur together. A careful neurological and functional assessment is essential.
How are SVAGs prescribed?
SVAGs are not an off-the-shelf pair of glasses. The evaluation should include:
- Confirmation and characterization of the visual-field defect.
- Assessment of visual acuity, ocular alignment, contrast, cognition, and visual attention.
- Discussion of specific functional problems.
- Demonstration of different prism configurations.
- Observation of the patient using the system during realistic tasks.
- Custom measurements and lens fabrication.
- Training and follow-up after dispensing.
General eye care practitioners do not have to prescribe the system themselves. Their most important role may be recognizing the functional problem and referring the patient to a low-vision or neuro-optometric practitioner experienced with hemianopia rehabilitation.
What Do Side Vision Awareness Glasses Look Like?
From a distance, SVAGs can look similar to conventional prescription glasses. Up close, another person may notice a vertical line where the standard lens area meets the prism portion.
These lenses generally appear less conspicuous than temporary Fresnel prisms. However, cosmetics should be a secondary consideration. The more important questions are whether the patient can interpret the shifted image, use it without excessive confusion, and gain meaningful functional awareness.
New Design: Exclusive to Midwest Low Vision
Typically, these glasses have a prism on the back of the lens so that someone can use it when they need to by shifting their eyes to the left or the right. However, Dr. Rummel generously gifted Dr. Jarrod Long a set of his brand new full-field side vision awareness glasses. They work similarly to the standard SVAG but the entire lens is specially designed to shift the missing part of your vision into view. This expands a person’s awareness of objects in their path and enhances peripheral vision. Currently, Midwest Low Vision is one of the only practices in the Midwest with the full field SVAG.
New Full-Field SVAG design
This picture shows a pair of the new full-field glasses. Notice how there is no extra attachment on either lens- instead, the entire lens is designed to adjust the field of view. You can see how the lens shifts the image of the eye chart to the left. This specific type of lens is ideal for someone missing their right visual field. The new design allows someone to see more of their side vision without compromising the view right in front of them.
Frequently Asked Questions
How do SVAGs differ from Peli peripheral prism glasses?
The two systems redirect information from the blind side, but they use different optical arrangements. SVAGs use a vertically oriented prism area beside the central viewing area, requiring the wearer to deliberately look briefly into the side prism area. They usually have a faint vertical dividing line between the conventional lens and prism area, and are intended to provide a relatively large, clear area through which the shifted scene can be inspected.
In contrast, Peli peripheral prisms use prism segments above and below the central line of sight to provide peripheral awareness while central vision remains unobstructed. They may begin with visible Fresnel press-on segments and later be made as permanent prism segments, and they are intended primarily to alert the wearer to objects in the blind-side peripheral field.
SVAG developers report better optical clarity and contrast than Fresnel press-on prisms. That comparison is optically plausible because Fresnel material introduces blur and contrast loss, but it should not be presented as proof that SVAGs are superior to permanent Peli lenses. The Peli design has substantially more peer-reviewed clinical research supporting its use as a mobility aid. Community studies found that some patients continued using Peli prisms because they were helpful for obstacle avoidance, although not everyone adapted or continued wearing them.
Therefore, the best system is not determined by appearance or prism power alone. It depends on the patient’s field loss, visual processing, cognition, mobility needs, ability to learn the system, and response during an in-office trial.
They require training and practice. Initially, the shifted image may feel unfamiliar, displaced, or confusing. The wearer must learn:
- To recognize an image appearing in the prism area.
- To use it as an alert rather than assuming the object is in the apparent location.
- To turn the eyes and head toward the object.
- To confirm its actual position through the clear portion of the lens.
- To incorporate the technique into walking, shopping, social situations, and other daily activities.
A properly prescribed device should be paired with structured instruction—not simply dispensed with the expectation that the patient will “figure it out.”
Can SVAGs be worn all day?
Some people may wear them for extended periods, while others use them primarily for mobility or visually complex environments.
The right wearing schedule depends on the design and the patient’s goals. Prism field-expansion systems may be less helpful for sustained reading, computer work, or other detailed central tasks. Some patients benefit from a separate pair of glasses for walking and daily mobility.
Can SVAGs help someone qualify to drive?
Possibly in isolated cases, but these glasses should never be described as a route to “passing the vision test.”
Driver-licensing requirements vary by jurisdiction, and many people with homonymous hemianopia do not meet the required horizontal visual field. A prism may increase awareness without restoring the underlying field or automatically satisfying a licensing standard.
Oblique Peli prisms can provide approximately 30 degrees of expansion in parts of the visual field and have been studied in driving-related detection tasks. Research found that peripheral prisms, particularly when combined with perceptual-motor training, improved blind-side hazard detection in a driving simulator. That does not prove that every wearer is safe to drive or legally qualified. Peripheral prisms and driving-simulator detection
Any discussion of returning to driving should include:
- Current state licensing requirements.
- Formal binocular visual-field testing.
- Assessment of visual attention, processing speed, cognition, and motor function.
- Training in prism use when applicable.
- Evaluation by a certified driver rehabilitation specialist.
- Behind-the-wheel assessment and approval by the licensing authority when required.
In Indiana, the BMV may require documentation from an optometrist or ophthalmologist and may apply restrictions such as corrective lenses, additional mirrors, or daylight-only driving. The BMV—not the prescribing doctor or the glasses—makes the licensing determination.
Conclusion
Dr. Long is specially trained to prescribe and dispense the right pair of glasses for you or your loved ones. If this sounds like something that would improve your quality of life, please call for more information!
