Study Type: Prospective, randomized, parallel-group clinical trial.
Participants: Children aged 4-8 years with unilateral amblyopia; amblyopic-eye BCVA between 0.17-0.67 decimal (≈ 6/36-6/9); fellow-eye BCVA ≥ 0.80 decimal; refractive-dominant or strabismic/mixed amblyopia. Parental/guardian consent required.
Randomization \& Stratification: Participants randomized 1:1 to "Morning patching" vs "Evening patching" arms. Stratified by age (4-\<6 vs \>=6-8), baseline visual acuity or amblyopia severity (moderate 6/36-\<6/12 vs mild 6/12-6/9), and amblyopia type (refractive-dominant vs strabismic/mixed) - to ensure balance across key prognostic variables.
Intervention: Daily occlusion of the non-amblyopic eye for 2 continuous hours, at assigned time window (Morning: 08:00-10:00; Evening: 17:00-19:00). During patching, child engages in near-vision tasks (reading, puzzles, coloring) for 20-30 min or more. Adherence monitored via parent diary/photos. Spectacle correction (if prescribed) maintained throughout.
Follow-up / Assessments:
Baseline exam (BCVA both eyes, refraction, ocular alignment/strabismus assessment, anterior and posterior segment exam, stereoacuity, instructions on patching/adherence, randomization).
Midpoint follow-up at 3 months (BCVA, adherence, adverse events. Telehealth acceptable if in-person not possible.).
Final follow-up at 6 months (BCVA (primary endpoint), stereoacuity, ocular alignment/strabismus assessment, anterior segment exam, adherence data review, adverse events, patching compliance summary.).
Primary Outcome: Change in best-corrected visual acuity (BCVA) of the amblyopic eye from baseline to month 6.
Secondary Outcomes: Stereoacuity improvement, adherence rate (% of days/patching sessions completed).
Statistical Approach: Analysis of covariance (ANCOVA) comparing mean change in BCVA between arms, adjusting for baseline VA and stratification factors. Subgroup analyses by amblyopia type, baseline severity, age group.
Sample Size / Power (Summary):
Target total enrollment \~100 children (≈ 50 per arm), to provide sufficient power to detect a clinically meaningful difference (≈ 1 line difference in BCVA) between morning and evening patching, while allowing for variability, drop-outs, and stratified analyses.
Duration \& Timeline:
Each participant will be followed for 6 months of daily patching. The total study duration (from first enrollment to last follow-up) will depend on recruitment rate; estimated duration \~ 7-9 months including recruitment, follow-up, data cleaning, and analysis.
Significance \& Expected Impact:
If timing of occlusion influences visual outcome, this could refine occlusion therapy recommendations - potentially improving efficacy, adherence, and convenience for patients and families. The trial may identify a more effective or practical patching schedule, thereby contributing to evidence-based amblyopia management.
