Clinical Trial of Multi-Periscopic Prism Glasses for Hemianopia

Randomized Controlled Multicenter Clinical Trial of Multi-Periscopic Prism Glasses for Homonymous Hemianopia

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).

Study Overview

• Status: Active, not recruiting
• Conditions: Homonymous Hemianopia
• Intervention / Treatment: Device: Multi-Periscopic Prism (MPP) glasses; Device: Fresnel Peripheral Prism (FPP) glasses

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.

• Study Type: Interventional
• Enrollment (Actual): 64
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Alabama
    • Birmingham, Alabama, United States, 35233
      • UAB Center for Low Vision Rehabilitation, Callahan Eye Hospital
  • Colorado
    • Denver, Colorado, United States, 80045
      • UCHealth Sue Anschutz-Rodgers Eye Center
  • Florida
    • Palm Springs, Florida, United States, 33461
      • Visual Health and Surgical Center
  • Illinois
    • Chicago, Illinois, United States, 60616
      • Illinois College of Optometry
  • Massachusetts
    • Boston, Massachusetts, United States, 02114
      • Schepens Eye Research Institute
    • Boston, Massachusetts, United States, 02215
      • New England College of Optometry
    • Worcester, Massachusetts, United States, 01655
      • UMass Chan Medical School
    • Worcester, Massachusetts, United States, 01608
      • The Eye and Vision Center at MCPHS

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 7 years and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 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.	Device: Multi-Periscopic Prism (MPP) glasses; Spectacles with multi-periscopic prisms mounted as oblique peripheral prism segments; Device: Fresnel Peripheral Prism (FPP) glasses; Spectacles with conventional permanent Fresnel prisms mounted as oblique peripheral prism segments
Experimental: 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.	Device: Multi-Periscopic Prism (MPP) glasses; Spectacles with multi-periscopic prisms mounted as oblique peripheral prism segments; Device: Fresnel Peripheral Prism (FPP) glasses; Spectacles with conventional permanent Fresnel prisms mounted as oblique peripheral prism segments

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Improvement in Blind-side Detection Rate for Hazards Approaching at a Bearing Angle of 40 Degrees	Improvement in detection rate with prism glasses for hazards approaching from the blind side at a bearing angle of 40 degrees in the VR walking simulator test. Improvement is a binary outcome, defined as blind-side detection rate (number of pedestrians detected as a percentage of the total number of pedestrian events) which is significantly higher (z-test for two proportions) with than without prism glasses at the same visit.	Immediately after each 4-week intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Improvement in Blind-side Detection Rate for Hazards Approaching at a Bearing Angle of 20 Degrees	Improvement in detection rate with prism glasses for hazards approaching from the blind side at a bearing angle of 20 degrees in the VR walking simulator test. Improvement is a binary outcome, defined as blind-side detection rate (number of pedestrians detected as a percentage of the total number of pedestrian events) which is significantly higher (z-test for two proportions) with than without prism glasses at the same visit.	Immediately after each 4-week intervention
Device Preference	Number of participants selecting each device as a percentage of the total number of participants enrolled	Immediately after the second 4-week intervention

Collaborators and Investigators

• Sponsor: Massachusetts Eye and Ear Infirmary
• Collaborators: National Eye Institute (NEI)
• Investigators: Principal Investigator: Eli Peli, OD MSc, Schepens Eye Research Institute of Massachusetts Eye and Ear

Study record dates

Study Major Dates

• Study Start (Actual): October 3, 2022
• Primary Completion (Actual): April 30, 2025
• Study Completion (Estimated): April 30, 2026

Study Registration Dates

• First Submitted: March 25, 2021
• First Submitted That Met QC Criteria: March 31, 2021
• First Posted (Actual): April 1, 2021

Study Record Updates

• Last Update Posted (Actual): March 13, 2026
• Last Update Submitted That Met QC Criteria: February 20, 2026
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Eye Diseases; Vision Disorders; Sensation Disorders; Blindness; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Hemianopsia; Equipment and Supplies; Optical Devices; Lenses; Eyeglasses
• Other Study ID Numbers: MPPvsFPP; R01EY023385 (U.S. NIH Grant/Contract)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No