OBJECTIVE

After treatment with refractive correction and patching, some patients have residual amblyopia resulting from strabismus or anisometropia. We conducted a clinical trial to evaluate the effectiveness of increasing prescribed daily patching from 2 to 6 hours in children with stable residual amblyopia.

DESIGN

Prospective, randomized, multicenter clinical trial.

PARTICIPANTS

A total of 169 children aged 3 to <8 years (mean, 5.9 years) with stable residual amblyopia (20/32-20/160) after 2 hours of daily patching for at least 12 weeks.

INTERVENTION

Random assignment to continue 2 hours of daily patching or increase patching time to an average of 6 hours/day.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (VA) in the amblyopic eye after 10 weeks.

RESULTS

Baseline VA was 0.44 logarithm of the minimum angle of resolution (logMAR) (20/50(-2)). Ten weeks after randomization, amblyopic eye VA had improved an average of 1.2 lines in the 6-hour group and 0.5 line in the 2-hour group (difference in mean VA adjusted for acuity at randomization = 0.6 line; 95% confidence interval, 0.3-1.0; P = 0.002). Improvement of 2 or more lines occurred in 40% of participants patched for 6 hours versus 18% of those who continued to patch for 2 hours (P = 0.003).

CONCLUSIONS

When amblyopic eye VA stops improving with 2 hours of daily patching, increasing the daily patching dosage to 6 hours results in more improvement in VA after 10 weeks compared with continuing 2 hours daily.