Clinical trial NCT05394987: Optical Correction and Visual Functions of Adults With Amblyopia
Official title: Spectacle Correction for the Treatment of Amblyopia
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Amblyopia
Keywords: Amblyopia
Binocular vision
Suppression
Plasticity
Optical correction
Lead sponsor: Centre for Eye and Vision Research
Sponsor class: OTHER
Collaborators: name: The Hong Kong Polytechnic University
name: University of Waterloo
First posted: 2022-05-27
Enrollment: 36
Sex: ALL
Minimum age (years): 18
Maximum age (years): 39
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: Within-subject, pre-post interventional study, measuring the effect of optical correction on visual function.
Primary purpose: TREATMENT

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.


Eligibility criteria: Inclusion Criteria:

* 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

Exclusion Criteria:

* 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

Primary outcomes:
measure: Best corrected visual acuity of the amblyopic eye pre-intervention
timeFrame: Approx. 5 mins, baseline (day 1 of spectacle wear)
measure: Best corrected visual acuity of the amblyopic eye post-intervention
timeFrame: Approx. 5 mins, on completion of study (week 24)
Secondary outcomes:
measure: Best corrected visual acuity of the amblyopic eye during intervention
timeFrame: Approx. 5 mins, every 4 weeks from start of intervention
measure: Fellow eye distance visual acuity pre-intervention
timeFrame: Approx. 5 mins, baseline (day 1 of spectacle wear)
measure: Fellow eye distance visual acuity post-intervention
timeFrame: Approx. 5 mins, on completion of study (week 24)
measure: Fellow eye distance visual acuity during-intervention
timeFrame: Approx. 5 mins, every 4 weeks from start of intervention
measure: Binocular distance visual acuity pre-intervention
timeFrame: Approx. 5 mins, baseline (day 1 of spectacle wear)
measure: Binocular distance visual acuity post-intervention
timeFrame: Approx. 5 mins, on completion of study (week 24)
measure: Binocular distance visual acuity during intervention
timeFrame: Approx. 5 mins, every 4 weeks from start of intervention
measure: Near visual acuity of amblyopic eye pre-intervention
timeFrame: Approx. 5 mins, baseline (day 1 of spectacle wear)
measure: Near visual acuity of amblyopic eye post-intervention
timeFrame: Approx. 5 mins, on completion of study (week 24)
measure: Near visual acuity of amblyopic eye during intervention
timeFrame: Approx. 5 mins,every 4 weeks from start of intervention
measure: Near visual acuity of fellow eye pre-intervention
timeFrame: Approx. 5 mins, baseline (day 1 of spectacle wear)
measure: Near visual acuity of fellow eye post-intervention
timeFrame: Approx. 5 mins, on completion of study (week 24)
measure: Near visual acuity of fellow eye during intervention
timeFrame: Approx. 5 mins, every 4 weeks from start of intervention
measure: Near binocular visual acuity pre-intervention
timeFrame: Approx. 5 mins, baseline (day 1 of spectacle wear)
measure: Near binocular visual acuity post-intervention
timeFrame: Approx. 5 mins, on completion of study (week 24)
measure: Near binocular visual acuity during intervention
timeFrame: Approx. 5 mins, every 4 weeks from start of intervention
measure: Amblyopic eye contrast sensitivity pre-intervention
timeFrame: Approx. 10 mins, baseline (day 1 of spectacle wear)
measure: Amblyopic eye contrast sensitivity post-intervention
timeFrame: Approx. 10 mins, on completion of study (week 24)
measure: Amblyopic eye contrast sensitivity during intervention
timeFrame: Approx. 10 mins, every 4 weeks from start of intervention
measure: Stereopsis pre-intervention
timeFrame: Approx. 5 mins, baseline (day 1 of spectacle wear)
measure: Stereopsis post-intervention
timeFrame: Approx. 5 mins, on completion of study (week 24)
measure: Stereopsis during intervention
timeFrame: Approx. 5 mins, every 4 weeks from start of intervention
measure: Angle of strabismus pre-intervention
timeFrame: Approx. 5 mins,baseline (day 1 of spectacle wear)
measure: Angle of strabismus post-intervention
timeFrame: Approx. 5 mins, on completion of study (week 24)
measure: Angle of strabismus during intervention
timeFrame: Approx. 5 mins, every 4 weeks from start of intervention
measure: Amblyopic eye fixation stability pre-intervention
timeFrame: Approx. 5 mins, baseline (day 1 of spectacle wear)
measure: Amblyopic eye fixation stability post-intervention
timeFrame: Approx. 5 mins, on completion of study (week 24)
measure: Amblyopic eye fixation stability during intervention
timeFrame: Approx. 5 mins, every 4 weeks from start of intervention
measure: Fellow (non-amblyopic) eye fixation stability pre-intervention
timeFrame: Approx. 5 mins, baseline (day 1 of spectacle wear)
measure: Fellow (non-amblyopic) eye fixation stability post-intervention
timeFrame: Approx. 5 mins, on completion of study (week 24)
measure: Fellow (non-amblyopic) eye fixation stability during intervention
timeFrame: Approx. 5 mins, every 4 weeks from start of intervention
measure: Interocular suppression pre-intervention
timeFrame: Approx. 10 mins, baseline (day 1 of spectacle wear)
measure: Interocular suppression post-intervention
timeFrame: Approx. 10 mins, on completion of study (week 24)
measure: Interocular suppression during intervention
timeFrame: Approx. 10 mins, every 4 weeks from start of intervention
measure: Quality of life pre-intervention
timeFrame: Approx.15-20 mins, baseline (day 1 of spectacle wear)
measure: Quality of life post-intervention
timeFrame: Approx. 15-20 mins, on completion of study (week 24)
Other outcomes:
measure: Electrical potentials pre-intervention
timeFrame: Approx. 60 mins, baseline (day 1 of spectacle wear)
measure: Electrical potentials post-intervention
timeFrame: Approx. 60 mins, on completion of study (week 24)
measure: Electrical potentials during intervention
timeFrame: Approx. 60 mins, 12 weeks from baseline (day 1 of spectacle wear)
Locations:
city: Waterloo
country: Canada
facility: University of Waterloo
state: Ontario
city: Hong Kong
country: Hong Kong
facility: Centre for Eye and Vision Research Limited
state: Guangdong
Study officials:
affiliation: Centre for Eye and Vision Research Limited
name: Benjamin Thompson, PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: Centre for Eye and Vision Research Limited
name: Ken WS Tan, PhD
role: STUDY_DIRECTOR
References: