Optical Correction and Visual Functions of Adults With Amblyopia

Summary

Amblyopia is a developmental anomaly resulting from abnormal visual experiences in early life. Amblyopia causes reduced visual acuity in the absence of a pathology. Adult sensory systems are believed to be structurally invariant beyond early, critical periods of development. However, recent evidence suggest that visual functions in adults with amblyopia can be improved with optical correction alone. This study aims to investigate whether improvements in best corrected visual acuity and other visual functions can result following appropriate optical correction in adults with amblyopia. Functional measures relating to vision, binocular vision, and eye movements will be used to assess the efficacy of refractive correction for improving vision. This study will help us better understand the improvements in visual functions following optical correction, as well as the mechanisms underlying neuroplasticity in adults with amblyopia.

Conditions

• Amblyopia

Interventions

DEVICE

Spectacles

Prescription of refractive error correction in spectacles. Refractive error to be determined as part of standard optometric eye exam (performed by registered optometrist). Guidelines for optical correction for the prescription of the study spectacles (based on Pediatric Eye Disease Investigator Group \[PEDIG\] amblyopia clinical trial protocols): Hypermetropia: not undercorrected by \>+1.50D spherical equivalent and the reduction in plus sphere must be identical between the two eyes. Anisometropia: full correction of the anisometropic difference. Astigmatism: cylinder power in each eye should be within ≤±0.50D of fully correcting the astigmatism for each eye. If cylinder power is ≥1.00D, the prescribed axis in both eyes should be within ≤±6 deg of the cycloplegic refraction axis. Appropriate refractive error correction will be prescribed. Participants will be instructed to wear the optical correction full-time (i.e., \>50% of waking hours) for the duration of the study.

Sponsors & Collaborators

• The Hong Kong Polytechnic University

  collaborator OTHER

• University of Waterloo

  collaborator OTHER

• Centre for Eye and Vision Research

  lead OTHER

Principal Investigators

• Benjamin Thompson, PhD · Centre for Eye and Vision Research Limited

• Ken WS Tan, PhD · Centre for Eye and Vision Research Limited

Study Design

Allocation

NA

Purpose

TREATMENT

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

39 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2022-06-13

Primary Completion

2026-11-30

Completion

2027-05-31

Countries

• Canada
• Hong Kong

Study Locations