The effect of increasing doses of levodopa on children with strabismic amblyopia

The purpose of this study was to determine the efficacy and tolerance of a levodopa/carbidopa combination and to test its dose-effect response when combined with occlusion therapy for children with amblyopia.

A 1-week randomized, double-blind, parallel, and placebo-controlled study was performed with 78 children with amblyopia aged between 7 and 17 years. Children who weighed less than 40 kg were randomly assigned to receive 5, 10, or 20 mg of levodopa or placebo (3 times a day), and those who weighed 40 kg or more were randomly assigned to receive 10, 20, or 40 mg of levodopa or placebo. Subjects were instructed to occlude the dominant eye (3 h/d). Snellen visual acuity was measured at baseline and at 2 hours after ingestion of the last capsule. Compliance with occlusion and capsule consumption was verified by a questionnaire and counting capsules. Adverse effects were checked with a physical examination and a questionnaire.

From baseline to the follow-up test trial, the improvement in the logarithm of the Snellen fraction was 0.05+/-0.11 in the placebo group, 0.18 +/-0.21 in group 1, 0.08+/-0.11 in group II, and 0.16+/-0.15 in group III (P = .031). Visual acuity improved from 0.59 to 0.45 in the levodopa/carbidopa group and from 0.69 to 0.63 in the control group (P = .023). The compliance with occlusion was similar in all groups. No one complained of adverse side effects.

Levodopa, at an average dose of 0.51 mg/kg per day, is well tolerated and produces a clinical and statistically significant short-term improvement of visual acuity in children with amblyopia.