RecruitingNot ApplicableNCT05394987

Optical Correction and Visual Functions of Adults With Amblyopia

Spectacle Correction for the Treatment of Amblyopia


Sponsor

Centre for Eye and Vision Research

Enrollment

36 participants

Start Date

Jun 13, 2022

Study Type

INTERVENTIONAL

Conditions

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.


Eligibility

Min Age: 18 YearsMax Age: 39 Years

Inclusion Criteria6

  • (inclusive) years of age
  • Anisometropic amblyopia (difference of ≥0.50D spherical equivalent or ≥1.50D astigmatism between eyes) or mixed mechanism amblyopia (strabismus and anisometropia)
  • Best corrected visual acuity (BCVA) in the amblyopic eye of 0.3 logMAR to 1.0 logMAR (inclusive)
  • BCVA in the non-amblyopic eye of 0.1 logMAR or better, and an interocular VA difference of 2 logMAR lines or more
  • Difference of 1.00D or more between current refractive correction and study prescription
  • Good general health

Exclusion Criteria11

  • Other pathological ocular anomalies known to cause reduced visual acuity
  • Presbyopia (based on amplitude of accommodation)
  • Inability to tolerate prescribed refractive correction in spectacles (e.g., due to aniseikonia)
  • Contraindication to cycloplegic eye drops
  • Currently under amblyopia treatment/therapy
  • Inability to comprehend test instructions and/or provide consent
  • Eccentric fixation
  • \>-6.00DS of myopia in either eye with spectacles
  • Bilateral amblyopia
  • Presence of amblyopia that is not due to strabismus and/or anisometropia
  • Presence of (current or previous) psychiatric, visual, or neurological disorders

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Interventions

DEVICESpectacles

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.


Locations(2)

University of Waterloo

Waterloo, Ontario, Canada

Centre for Eye and Vision Research Limited

Hong Kong, Guangdong, Hong Kong

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NCT05394987


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