Longitudinal study of levodopa/carbidopa for childhood amblyopia

Abstract

To determine the tolerability and efficacy of levodopa/carbidopa combined with occlusion therapy for childhood amblyopia, a double-masked placebo-controlled randomized longitudinal study was performed on 10 amblyopic children between 6 and 14 years of age. Subjects received, on average, 20/5 mg levodopa/carbidopa or 20 mg of placebo three times per day combined with part-time occlusion over a 3-week period. Visual function was assessed by Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity charts and by contrast sensitivity. Tolerability was assessed by questionnaire, SMAC (standard laboratory tests; consists of a chem 20 and complete blood count [CBC]) analysis, and physical examination. Compliance with occlusion and capsule consumption were assessed by questionnaire and by capsule count, respectively. At the end of the dosing regimen, the levodopa/carbidopa group significantly improved in visual acuity by 2.7 lines and in mean contrast sensitivity by 72% in the amblyopic eye. The placebo group improved in visual acuity by 1.6 lines in the amblyopic eye. Tolerability and occlusion compliance were similar between groups; however, capsule ingestion compliance was significantly lower in the levodopa/carbidopa group. One month after the termination of treatment, the levodopa/carbidopa group maintained a significant 1.2-line improvement in visual acuity and 74% improvement in contrast sensitivity in the amblyopic eye. The placebo group did not maintain an improvement in visual acuity between the eyes. It is concluded that levodopa/carbidopa, at an average of 0.48/0.12 mg/kg, is well tolerated and, when combined with part-time occlusion, is efficacious in improving visual function in amblyopic children.