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RecruitingNCT04424979Updated Sep 23, 2025

Feasibility Tests for Various Prism Configurations for Visual Field Loss

An interventional study of High power prisms in Hemianopia, Homonymous, Tunnel Vision and Visual Field Defect, Peripheral, sponsored by Massachusetts Eye and Ear Infirmary. Recruiting at 1 site in United States. Open to participants aged 7 Years to 80 Years. Per ClinicalTrials.gov, last updated 2025-09-23.

Sponsored by Massachusetts Eye and Ear Infirmary · Not applicable, Interventional, and Device feasibility

Phase
Not applicable
Study type
Interventional
Enrollment
20
Allocation
Not applicable
Ages
7 Years to 80 Years
Sex
All
01

Study summary

The investigators will develop and test different configurations of high-power prisms to expand the field of vision of patients with visual field loss to assist them with obstacle detection when walking. The study will involve multiple visits (typically four) to Schepens Eye Research Institute for fitting and testing with the prism glasses. The overall objective is to determine best designs and fitting parameters for implementation in prism devices for future clinical trials.

02

Conditions studied

  • Hemianopia, Homonymous
  • Tunnel Vision
  • Visual Field Defect, Peripheral
  • Visual Field Constriction Bilateral
  • Visual Field Defect Homonymous Bilateral

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Keywords

  • Visual field expansion
  • Prisms
  • Hemianopsia
  • Tunnel vision
  • Visual field loss
03

Who can participate

Ages eligible
7 Years to 80 Years
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  • Visual field loss, either peripheral field loss or hemianopic field loss
  • Visual acuity of at least 20/50 in the better eye
  • In sufficiently good health to be able to complete sessions lasting 2-4 hours
  • Able to independently walk short distances
  • Able to give voluntary, informed consent
  • Able to speak English

Exclusion criteria

Exclusion Criteria:

  • Any physical or mental impairments, including cognitive dysfunction, balance problems or other deficits that could impair the ability to walk or use the prism spectacles
  • A history of seizures in the last 6 months
  • Hemispatial neglect (subjects with hemianopic field loss only)
04

Study design

Phase
Not applicable
Primary purpose
Device feasibility
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
20 participants (estimated)

Study arms

  • Experimental
    High power prisms

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

    Device: High power prisms

Interventions

  • DeviceHigh power prisms

    High power prisms designed to shift images from blind areas into portions of the wearer's remaining, seeing, field of vision

05

What researchers measure

Primary outcomes

  1. Field of view expansion

    Horizontal and vertical extent of the expansion (in degrees) of the field of view

    Time frame: Through study completion, an average of four months

Secondary outcomes

  1. Pedestrian detection rate

    Proportion of pedestrians detected (in simulated walking or simulated driving)

    Time frame: Through study completion, an average of four months

06

Study locations

1 of 1 sites recruiting
  • Schepens Eye Research Institute
    Boston, Massachusetts 02114, United States
    Recruiting
07

References and documents

Publications

  • Bowers AR, Manda S, Shekar S, Hwang AD, Jung JH, Peli E. Pilot study of a pedestrian collision detection test for a multisite trial of field expansion devices for hemianopia. Optom Vis Sci. 2024 Jun 1;101(6):408-416. doi: 10.1097/OPX.0000000000002152. PubMed 38990239 ↗

Individual participant data

Plan to share: No

08

Registry details

Key details

Study ID
NCT04424979
Lead sponsor
Massachusetts Eye and Ear Infirmary
Collaborators
National Eye Institute (NEI)
Responsible party
Alexandra Bowers (Associate Professor, Massachusetts Eye and Ear Infirmary) — Principal investigator
First posted
Jun 11, 2020
Start date
Nov 6, 2020
Primary completion
Aug 2026 (estimated)
Completion
Dec 2026 (estimated)
Last update
Sep 23, 2025

Study contacts

Alex Bowers
Contact
alex_bowers@meei.harvard.edu
617 912 2512
Eliezer Peli, MSc, OD
study director · Schepens Eye Research Institute of Massachusetts Eye and Ear

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
Yes
View the source record on ClinicalTrials.gov ↗

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