Study: Young children with mild amblyopia show little benefit from treatment

Children with mild unilateral acuity loss demonstrated no benefit from treatment earlier than age 5, whereas children with poorer acuity fared better in a U.K. study. The study authors argue that children with acuity of 6/9 in only one eye should not be candidates for treatment.

M.P. Clarke and colleagues at the University of Newcastle upon Tyne, England, and elsewhere studied 177 children between the ages of 3 and 5 who had mild to moderate unilateral impairment of acuity. Mild to moderate impairment was defined as acuity of 6/9 to 6/36. Children were randomized to full treatment with glasses and patching, glasses only or no treatment. After 1 year follow-up, masked researchers assessed best corrected acuity.

Children in the full and glasses treatment groups had incrementally better visual acuity at follow-up than children who received no treatment, but the mean treatment effect was equivalent only to one Snellen line. Initial acuity was more of a determinant for success than age at enrollment. Full treatment showed a substantial effect in the moderate acuity group (6/36 to 6/18 at recruitment) and no significant effect in the mild acuity group (6/9 to 6/12 at recruitment).

The 64 children with moderate acuity loss effectively gained one to two Snellen lines. Six months after the trial ended, no significant difference in acuity between the groups was noted.

“Children with a moderate acuity loss of 6/18 or worse showed a clear cut response to treatment, which itself arguably justifies screening to identify and treat these children,” the authors reported in the December issue of British Medical Journal. However, they said, children with mild acuity loss — which in this and other studies often represents 50% or more of the enrolled subjects — “received little benefit from either treatment.”