Factors associated with recurrence of amblyopia on cessation of patching

In a prospective observational study, we previously reported that weaning (tapering or gradually reducing) treatment in children treated with 6 to 8 hours of daily patching for amblyopia resulted in a 4-fold reduction in odds of recurrence. We now report the association of additional factors with recurrence or regression of amblyopia in this same cohort.

Prospective, nonrandomized, observational study.

Sixty-nine children aged <8 years with successfully treated anisometropic or strabismic amblyopia (improved > or =3 logarithm of the minimum angle of resolution [logMAR] lines).

Patients were enrolled at the time they stopped patching for amblyopia. Patients were classified according to whether patching was stopped abruptly or weaned before cessation. They were followed off treatment for 52 weeks to assess recurrence of amblyopia.

Recurrence of amblyopia defined as a > or =2-logMAR level reduction of visual acuity from enrollment (cessation of patching) confirmed by a second examination. Recurrence was also considered to have occurred if treatment was restarted with a > or =2-logMAR level reduction of visual acuity, even if it was not confirmed by a second examination.

The risk of recurrence was higher with better visual acuity at the time of cessation of treatment (adjusted risk ratio [RR], 0.68 per line of worse visual acuity; 95% confidence interval [CI], 0.51-0.90), a greater number of lines improved during the previous treatment (adjusted RR, 1.5 per line increase; 95% CI, 1.1-2.0), and a history of recurrence (adjusted RR, 2.7; 95% CI, 1.5-4.9). Orthotropia or excellent stereoacuity at the time of patching cessation did not appear to have a protective effect on the risk of recurrence.

The higher risk of recurrence in the most successfully treated children with amblyopia and absence of protection from orthotropia and excellent random dot stereoacuity suggests that careful and prolonged follow-up is needed for all children who have been previously treated for amblyopia.