The purpose of the present study is to determine how long visual function improves during levodopa/carbidopa with part-time occlusion treatment in older amblyopic children. A 7-week open clinical trial of levodopa (0.55 mg/kg, three times daily) with 25% carbidopa combined with part-time occlusion (3 hours/day), was undertaken in 15 older (mean age, 8.87 years) amblyopic children. Visual acuity, fusion, and stereo acuity were measured at baseline, at weeks 1, 3, 5, and 7 during treatment, and 6 weeks following the end of all treatment. Health status was assessed by physical examination, questionnaire, and standard laboratory tests (CHEM 20, complete blood cell count [CBC], and differential). The results revealed that visual acuity in the amblyopic eye improved for 5 weeks, from 20/170 at baseline to 20/107, then stabilized for the last 2 weeks. Visual acuity also improved in the dominant eye by 0.6 lines, from 20/19 to 20/16. At the 6-week follow up, visual acuity in the amblyopic eye remained at 20/107 (paired t = 4.78, df = 14, P < .001), a 37% improvement. Thirty-three percent of the subjects demonstrated improved fusion from baseline to the 7-week trial that was maintained at follow up (chi 2 = 3.97, P < .05). Stereo acuity did not significantly change. Physical exam (blood pressure, body temperature, respiration, heart rate) and standard laboratory tests remained normal and side effects were minimal.(ABSTRACT TRUNCATED AT 250 WORDS)