Optical Correction and Visual Functions of Adults With Amblyopia
- Conditions
- Amblyopia
- Interventions
- Device: Spectacles
- Registration Number
- NCT05394987
- Lead Sponsor
- Centre for Eye and Vision Research
- Brief 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.
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- RECRUITING
- Sex
- All
- Target Recruitment
- 36
- 18-39 (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
- 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
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- SINGLE_GROUP
- Arm && Interventions
Group Intervention Description Optical correction Spectacles Prescription of spectacles for full-time wear to correct refractive error
- Primary Outcome Measures
Name Time Method Best corrected visual acuity of the amblyopic eye pre-intervention Approx. 5 mins, baseline (day 1 of spectacle wear) The size of the smallest line of letters read accurately on an ETDRS chart.
Best corrected visual acuity of the amblyopic eye post-intervention Approx. 5 mins, on completion of study (week 24) The size of the smallest line of letters read accurately on an ETDRS chart.
- Secondary Outcome Measures
Name Time Method Best corrected visual acuity of the amblyopic eye during intervention Approx. 5 mins, every 4 weeks from start of intervention The size of the smallest line of letters read accurately on an ETDRS chart.
Fellow eye distance visual acuity pre-intervention Approx. 5 mins, baseline (day 1 of spectacle wear) The size of the smallest line of letters read accurately on an ETDRS chart.
Fellow eye distance visual acuity during-intervention Approx. 5 mins, every 4 weeks from start of intervention The size of the smallest line of letters read accurately on an ETDRS chart.
Fellow eye distance visual acuity post-intervention Approx. 5 mins, on completion of study (week 24) The size of the smallest line of letters read accurately on an ETDRS chart.
Binocular distance visual acuity post-intervention Approx. 5 mins, on completion of study (week 24) The size of the smallest line of letters read accurately on an ETDRS chart.
Near visual acuity of amblyopic eye pre-intervention Approx. 5 mins, baseline (day 1 of spectacle wear) The size of the smallest line of letters read accurately on a near ETDRS chart.
Near visual acuity of fellow eye during intervention Approx. 5 mins, every 4 weeks from start of intervention The size of the smallest line of letters read accurately on a near ETDRS chart.
Near binocular visual acuity during intervention Approx. 5 mins, every 4 weeks from start of intervention The size of the smallest line of letters read accurately on a near ETDRS chart.
Stereopsis pre-intervention Approx. 5 mins, baseline (day 1 of spectacle wear) Smallest disparity on the Randot preschool test reported accurately.
Stereopsis during intervention Approx. 5 mins, every 4 weeks from start of intervention Smallest disparity on the Randot preschool test reported accurately.
Binocular distance visual acuity pre-intervention Approx. 5 mins, baseline (day 1 of spectacle wear) The size of the smallest line of letters read accurately on an ETDRS chart.
Binocular distance visual acuity during intervention Approx. 5 mins, every 4 weeks from start of intervention The size of the smallest line of letters read accurately on an ETDRS chart.
Near visual acuity of amblyopic eye post-intervention Approx. 5 mins, on completion of study (week 24) The size of the smallest line of letters read accurately on a near ETDRS chart.
Near visual acuity of amblyopic eye during intervention Approx. 5 mins,every 4 weeks from start of intervention The size of the smallest line of letters read accurately on a near ETDRS chart.
Near visual acuity of fellow eye pre-intervention Approx. 5 mins, baseline (day 1 of spectacle wear) The size of the smallest line of letters read accurately on a near ETDRS chart.
Near visual acuity of fellow eye post-intervention Approx. 5 mins, on completion of study (week 24) The size of the smallest line of letters read accurately on a near ETDRS chart.
Near binocular visual acuity pre-intervention Approx. 5 mins, baseline (day 1 of spectacle wear) The size of the smallest line of letters read accurately on a near ETDRS chart.
Near binocular visual acuity post-intervention Approx. 5 mins, on completion of study (week 24) The size of the smallest line of letters read accurately on a near ETDRS chart.
Amblyopic eye contrast sensitivity pre-intervention Approx. 10 mins, baseline (day 1 of spectacle wear) Computer-based measurement of contrast sensitivity
Amblyopic eye contrast sensitivity post-intervention Approx. 10 mins, on completion of study (week 24) Computer-based measurement of contrast sensitivity
Amblyopic eye contrast sensitivity during intervention Approx. 10 mins, every 4 weeks from start of intervention Computer-based measurement of contrast sensitivity
Stereopsis post-intervention Approx. 5 mins, on completion of study (week 24) Smallest disparity on the Randot preschool test reported accurately.
Angle of strabismus post-intervention Approx. 5 mins, on completion of study (week 24) Prismatic power required to neutralise the angle of deviation on alternating prism cover test.
Angle of strabismus during intervention Approx. 5 mins, every 4 weeks from start of intervention Prismatic power required to neutralise the angle of deviation on alternating prism cover test.
Fellow (non-amblyopic) eye fixation stability during intervention Approx. 5 mins, every 4 weeks from start of intervention Eye position recorded with high-speed eye tracker during fixation as quantified by bivariate contour ellipse area (BCEA).
Interocular suppression pre-intervention Approx. 10 mins, baseline (day 1 of spectacle wear) Computer-based measurement of interocular suppression.
Interocular suppression post-intervention Approx. 10 mins, on completion of study (week 24) Computer-based measurement of interocular suppression.
Quality of life pre-intervention Approx.15-20 mins, baseline (day 1 of spectacle wear) Questionnaire scores for:
1. Amblyopia and Strabismus Questionnaire
2. World Health Organization Quality of Life-BREFAngle of strabismus pre-intervention Approx. 5 mins,baseline (day 1 of spectacle wear) Prismatic power required to neutralise the angle of deviation on alternating prism cover test.
Amblyopic eye fixation stability pre-intervention Approx. 5 mins, baseline (day 1 of spectacle wear) Eye position recorded with high-speed eye tracker during fixation as quantified by bivariate contour ellipse area (BCEA).
Amblyopic eye fixation stability post-intervention Approx. 5 mins, on completion of study (week 24) Eye position recorded with high-speed eye tracker during fixation as quantified by bivariate contour ellipse area (BCEA).
Amblyopic eye fixation stability during intervention Approx. 5 mins, every 4 weeks from start of intervention Eye position recorded with high-speed eye tracker during fixation as quantified by bivariate contour ellipse area (BCEA).
Fellow (non-amblyopic) eye fixation stability pre-intervention Approx. 5 mins, baseline (day 1 of spectacle wear) Eye position recorded with high-speed eye tracker during fixation as quantified by bivariate contour ellipse area (BCEA).
Fellow (non-amblyopic) eye fixation stability post-intervention Approx. 5 mins, on completion of study (week 24) Eye position recorded with high-speed eye tracker during fixation as quantified by bivariate contour ellipse area (BCEA).
Interocular suppression during intervention Approx. 10 mins, every 4 weeks from start of intervention Computer-based measurement of interocular suppression.
Quality of life post-intervention Approx. 15-20 mins, on completion of study (week 24) Questionnaire scores for:
1. Amblyopia and Strabismus Questionnaire
2. World Health Organization Quality of Life-BREF
Trial Locations
- Locations (2)
University of Waterloo
🇨🇦Waterloo, Ontario, Canada
Centre for Eye and Vision Research Limited
🇭🇰Hong Kong, Guangdong, Hong Kong