Clinical Trial of Multi-Periscopic Prism Glasses for Hemianopia

NCT ID: NCT04827147

Last Updated: 2025-06-24

Basic Information

• Recruitment Status: ACTIVE_NOT_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 64 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-10-03
• Study Completion Date: 2026-04-30

Brief Summary

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 hemianopia (the complete loss of half the field of vision on the same side in both eyes).

Detailed Description

Patients with hemianopic field loss may be unaware of objects in their blind (non-seeing) hemi-field and often experience difficulties with hazards, such as walking into obstacles on the side of the field loss. Prism glasses that provide field of view expansion may be helpful in detecting hazards on the blind side. In this clinical trial, two types of high power prism glasses will be evaluated. A new design of prisms, Multi-Periscopic Prisms (MPP), will be compared to commercially-available permanent Fresnel peripheral prism (FPP) glasses. The extent to which the prismatic devices improve detection of hazards on the side of the field loss and are helpful when walking will be evaluated.

Participants will try each type of prism glasses at home for 4 weeks in counterbalanced order. Prism glasses will be fitted by Low Vision Practitioners at vision rehabilitation clinics. Participants will attend in-office study visits before and after wearing each type of prism glasses. At the in-office visits they will complete a test that involves detecting pedestrian hazards in a video simulating a walk through a busy shopping mall (virtual reality, VR, walking simulator test). In addition, they may be asked to complete questionnaires to record their experiences of using the prism glasses.

After wearing the second pair of prism glasses, participants will be asked to complete a questionnaire comparing the two types of prism glasses and to select their preferred type. A clinical decision will be made as to whether the participant should continue to use either the first or second pair of prism glasses (e.g. if a participant finds one pair of prism glasses helpful for obstacle avoidance when walking). For participants who continue with the prism glasses, telephone follow-up interviews will be conducted after about 6 and 12 months.

Conditions

Homonymous Hemianopia

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

MPP first, FPP second

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

Group Type: EXPERIMENTAL

Multi-Periscopic Prism (MPP) glasses

Intervention Type: DEVICE

Spectacles with multi-periscopic prisms mounted as oblique peripheral prism segments

Fresnel Peripheral Prism (FPP) glasses

Intervention Type: DEVICE

Spectacles with conventional permanent Fresnel prisms mounted as oblique peripheral prism segments

FPP first, MPP second

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

Group Type: EXPERIMENTAL

Multi-Periscopic Prism (MPP) glasses

Intervention Type: DEVICE

Spectacles with multi-periscopic prisms mounted as oblique peripheral prism segments

Fresnel Peripheral Prism (FPP) glasses

Intervention Type: DEVICE

Spectacles with conventional permanent Fresnel prisms mounted as oblique peripheral prism segments

Interventions

Multi-Periscopic Prism (MPP) glasses

Spectacles with multi-periscopic prisms mounted as oblique peripheral prism segments

Intervention Type: DEVICE

Fresnel Peripheral Prism (FPP) glasses

Spectacles with conventional permanent Fresnel prisms mounted as oblique peripheral prism segments

Intervention Type: DEVICE

Eligibility Criteria

Inclusion Criteria

• Homonymous hemianopia with or without macular sparing for at least 3 months
• Visual acuity of at least 20/50 in each eye, with correction if needed
• Refractive error in the -12D to +5D range
• Able to walk independently, using a cane or walker if needed
• Able to communicate in English sufficiently to understand the study procedures and how to use the prisms

Exclusion Criteria

• Central visual field loss in the seeing hemifield of either eye (e.g. from macular degeneration, glaucoma, diabetic retinopathy or other maculopathies)
• Hemi-spatial neglect
• Significant cognitive impairment
• Dementia
• Any other physical or mental disabilities, or general health problems that could impair the ability to be independently mobile (i.e., walk ), participate in the VR walking simulator test or use the prism glasses

• Minimum Eligible Age: 7 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

National Eye Institute (NEI)

NIH

Sponsor Role: collaborator

Massachusetts Eye and Ear Infirmary

OTHER

Sponsor Role: lead

Responsible Party

Eli Peli

Senior Scientist

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Eli Peli, OD MSc

Role: PRINCIPAL_INVESTIGATOR

Schepens Eye Research Institute of Massachusetts Eye and Ear

Locations

UAB Center for Low Vision Rehabilitation, Callahan Eye Hospital

Birmingham, Alabama, United States

UCHealth Sue Anschutz-Rodgers Eye Center

Denver, Colorado, United States

Visual Health and Surgical Center

Palm Springs, Florida, United States

Illinois College of Optometry

Chicago, Illinois, United States

Schepens Eye Research Institute

Boston, Massachusetts, United States

New England College of Optometry

Boston, Massachusetts, United States

The Eye and Vision Center at MCPHS

Worcester, Massachusetts, United States

UMass Chan Medical School

Worcester, Massachusetts, United States

Countries

United States

Other Identifiers

R01EY023385

Identifier Type: NIH

Identifier Source: secondary_id

View Link

MPPvsFPP

Identifier Type: -

Identifier Source: org_study_id