Prism Glasses for Visual Field Loss

Overseen By Alex Bowers

Age: Any Age

Sex: Any

Trial Phase: Academic

Sponsor: Massachusetts Eye and Ear Infirmary

Disqualifiers: Cognitive dysfunction, Balance problems, Seizures, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 4

Duration: 4 months

20 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial tests special glasses with high-power prisms to help people with visual field loss see better while walking. The main goal is to determine the best design and fit for these glasses, enabling users to detect obstacles more easily. Individuals who have lost part of their field of vision but can still see fairly well out of one eye and walk short distances independently may qualify for this trial. Participants will visit the research center several times to try different prism setups. As an unphased trial, this study provides a unique opportunity to contribute to innovative research that could enhance mobility for those with visual impairments.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications. It's best to discuss this with the trial coordinators or your doctor.

What prior data suggests that these prism glasses are safe for visual field loss?

Research shows that special glasses with high-power prisms can help people see more of their surroundings. Studies have examined these prisms for safety and effectiveness. Some participants reported seeing double, but this effect usually doesn't last long.

These prisms are particularly useful for individuals who have lost part of their vision, as they help expand the visible field. However, they might not prevent tripping over low-lying objects.

Overall, research indicates that these high-power prisms are generally safe, with only temporary issues like double vision. Prospective trial participants should inquire about possible side effects and discuss them with the study team. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Unlike standard treatments for visual field loss, which often rely on rehabilitation techniques or compensatory strategies, high power prisms offer a novel approach by redirecting light to expand the visual field. Researchers are excited about these prisms because they are custom-fitted into spectacle lenses, providing a personalized solution that directly addresses the individual's specific vision needs. This tailored approach not only aims to improve visual perception but also enhances overall quality of life, making it a promising alternative to existing methods.

What evidence suggests that high power prisms are effective for visual field loss?

Research has shown that special glasses with high-power prisms, provided to participants in this trial, can help individuals who have lost part of their vision see more of their surroundings. These prisms redirect light, enabling users to notice areas they might usually miss. Studies have found that wearing these prism glasses can improve obstacle detection while walking, enhancing mobility, especially for those with conditions like hemianopia, where half of the visual field is lost. Some trials noted that while these glasses can enhance vision-related quality of life, they might also cause visual discomfort for some users. Overall, prisms offer a promising way to help people see more of their environment. ^{4 6 7 8 9}

Who Is on the Research Team?

Eliezer Peli, MSc, OD

Principal Investigator

Schepens Eye Research Institute of Massachusetts Eye and Ear

Are You a Good Fit for This Trial?

This trial is for people with certain types of visual field loss, like tunnel vision or hemianopia. Participants must have at least 20/50 vision in their better eye, be able to walk on their own, speak English, and complete sessions up to 4 hours. It's not for those with recent seizures, balance issues that affect walking, cognitive problems, or hemispatial neglect.

Inclusion Criteria

I can complete activities lasting 2-4 hours without major issues.

You must be able to see at least 20/50 in your better eye.

I can walk on my own for short distances.

Exclusion Criteria

I do not have any physical or mental conditions that would stop me from walking or using special glasses.

I have had a seizure in the past 6 months.

I have difficulty noticing things on one side of my body.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants are fitted with various configurations of high-power prisms and tested for visual field expansion and obstacle detection

4 months

4 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• High power prisms

Trial Overview The study tests various high-power prism configurations designed to widen the visual field and help detect obstacles while walking. Participants will visit Schepens Eye Research Institute multiple times for fitting/testing these new prism glasses to find the best designs for future use.

How Is the Trial Designed?

Group I: High power prisms Experimental Treatment 1 Intervention

Various configurations of high power prisms will be developed for each individual and custom fit into spectacles lenses.

Who Is Running the Clinical Trial?

Massachusetts Eye and Ear Infirmary

Lead Sponsor

Trials

115

Recruited

15,000+

National Eye Institute (NEI)

Collaborator

Trials

572

Recruited

1,320,000+

Citations

1. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC3909527/

Impact of high power and angle of incidence on prism ... We analyze the effects of high prism power and incidence angle on the field expansion, size of the apical scotomas, and image compression/expansion.

2. clinicaltrials.gov clinicaltrials.gov/study/NCT04827147

Clinical Trial of Multi-Periscopic Prism Glasses for ... This clinical trial will evaluate the efficacy of two types of high-power prism glasses that provide field of view expansion for patients with homonymous ...

3. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC2680467/

Clinical and Laboratory Evaluation of Peripheral Prism ... We evaluated peripheral prism glasses as a low vision optical device for hemianopia in an extended wearing trial.

4. researchgate.net researchgate.net/publication/292708029_A_randomized_controlled_trial_comparing_the_effectiveness_of_prism_glasses_visual_search_training_and_standard_care_to_improve_visual_field_for_people_with_hemianopia_post_stroke

A randomized controlled trial comparing the effectiveness ... Visual search training had significant improvement in vision-related quality of life. Prism therapy produced adverse events in 69%. Visual ...

5. jamanetwork.com jamanetwork.com/journals/jamaophthalmology/fullarticle/420460

Community-Based Trial of a Peripheral Prism Visual Field ... Patients with HVFDs have difficulty detecting obstacles on the side of the loss, resulting in impaired mobility. The main vision-based ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC4424073/

Peripheral Prism Glasses: Effects of Moving and Stationary ... Peripheral prism glasses use high-power prism segments above and below the pupil to expand the visual field while users view centrally through the prism-free ...

7. clinicaltrials.gov clinicaltrials.gov/study/NCT00494676

Clinical Trial of Peripheral Prism Glasses for Hemianopia The purpose of this study is to evaluate the functional utility for general mobility (walking) of new high power permanent peripheral prism glasses.

8. jov.arvojournals.org jov.arvojournals.org/article.aspx?articleid=2592297

The risk of pedestrian collisions with peripheral visual field loss We do not expect prisms to help patients with tripping hazards, as even very high-power prisms (base down) cannot provide the hazard view needed, as shown in ...

9. opg.optica.org opg.optica.org/abstract.cfm?uri=boe-11-9-4872

Multi-periscopic prism device for field expansion Patients with field loss are able to monitor only a small fraction of the collision risks when walking in such open environments. Lateral eye ...