Prism Glasses for Hemianopia

Recruiting at 7 trial locations

Overseen By Alex Bowers, PhD

Age: Any Age

Sex: Any

Trial Phase: Academic

Sponsor: Massachusetts Eye and Ear Infirmary

Disqualifiers: Central visual field loss, Hemi-spatial neglect, Cognitive impairment, Dementia, others

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

Compensation: Varies

Number of Visits: 6

Duration: 8 weeks

63 Participants Needed

Trial Summary

What is the purpose of this trial?

This trial tests special glasses with powerful lenses to help people who have lost half of their vision on the same side in both eyes. The glasses work by bending light to expand their field of vision, making it easier to detect obstacles.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications.

Are prism glasses safe for humans?

Prism glasses, including Fresnel and multi-periscopic prisms, have been used in various conditions and are generally considered safe, though they may reduce visual clarity and disrupt depth perception. Some people find them more tolerable than having double vision, and they are often used in one eye to minimize these effects. ^{1 2 3 4 5}

How is the treatment with Prism Glasses for Hemianopia different from other treatments?

The Multi-Periscopic Prism (MPP) glasses offer a unique approach by providing a wider field of vision with 42° horizontal expansion and 18° vertical shift, along with high image quality and a broader eye scanning range, compared to traditional Fresnel prisms which have limited field expansion and image quality. ^{1 3 4 6 7}

Research Team

Eli Peli, OD MSc

Principal Investigator

Schepens Eye Research Institute of Massachusetts Eye and Ear

Eligibility Criteria

This trial is for individuals with homonymous hemianopia, which means they've lost half of their field of vision in both eyes. Participants must have at least 20/50 vision with correction, a refractive error within -12D to +5D, and be able to walk independently. They should not have conditions like dementia or significant cognitive impairment that would affect mobility or the use of prism glasses.

Inclusion Criteria

I can walk on my own, even if I need a cane or walker.

Your vision prescription falls outside of -12D to +5D range.

I have had partial vision loss in both eyes for at least 6 months.

Exclusion Criteria

You have dementia.

You have difficulty paying attention to one side of your body or environment.

I have vision loss in part of my field of view due to an eye condition.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants will try each type of prism glasses at home for 4 weeks in counterbalanced order

8 weeks

4 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment, including telephone follow-up interviews

12 months

2 telephone interviews

Treatment Details

Interventions

• Fresnel Peripheral Prism (FPP) glasses
• Multi-Periscopic Prism (MPP) glasses

Trial Overview The study is testing two types of prism glasses designed to expand the field of view: Multi-Periscopic Prism (MPP) glasses and Fresnel Peripheral Prism (FPP) glasses. The effectiveness of these glasses will be compared in helping patients navigate their environment.

Participant Groups

Group I: MPP first, FPP second Experimental Treatment 2 Interventions

Participants in this arm will receive the MPP in the first period of the crossover and the FPP in the second period.

Group II: FPP first, MPP second Experimental Treatment 2 Interventions

Participants in this arm will receive the FPP in the first period of the crossover and the MPP in the second period.

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+

References

1. United States pubmed.ncbi.nlm.nih.gov

Hemianopic Fresnel prisms. [2022]

2. United States pubmed.ncbi.nlm.nih.gov

Fresnel prisms and their effects on visual acuity and binocularity. [2018]

3. Germany pubmed.ncbi.nlm.nih.gov

[Fresnel prisms--their value in the rehabilitation of homonymous hemianopsias]. [2009]

4. United States pubmed.ncbi.nlm.nih.gov

Oblique multi-periscopic prism for field expansion of homonymous hemianopia. [2023]

5. England pubmed.ncbi.nlm.nih.gov

Fresnel prism correction for trauma-induced diplopia. [2006]

6. United States pubmed.ncbi.nlm.nih.gov

Fresnel prism therapy for right hemianopia. [2022]

7. United States pubmed.ncbi.nlm.nih.gov

Field expansion for homonymous hemianopia by optically induced peripheral exotropia. [2022]