Feasibility Tests for Various Prism Configurations for Visual Field Loss

Massachusetts Eye and Ear Infirmary20 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

Purpose

DEVICE_FEASIBILITY

Masking

NONE

Enrollment

Conditions

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

Eligibility

Sex: ALLMin age: 7 YearsMax age: 80 Years

Medical Language ↔ Plain English

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: * 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)

Outcomes

Primary Outcomes

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

Pedestrian detection rate

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