Effect of levodopa therapy on visual-evoked potentials and visual acuity in amblyopia

Amblyopia represents the most common form of visual impairment in children, affecting approximately 2% of the population. To determine the efficacy of the dopa mine agonist levodopa for childhood amblyopia, a double-masked, placebo-controlled randomised study was performed on 32 amblyopic children with central fixation between 4 and 17 years. Subjects received 2 mg/kg levodopa benzeraside or placebo 3 times per day over a 1 week period. Estimates of visual acuity for each eye (Snellen visual acuity) were obtained, and pattern-shift visually evoked potentials (VEP) were examined by an opthalmologist and a neurologist. At the end of the dosing regimens, the levodopa group was significantly improved in visual acuity by 1.4 lines and pattern VEP amplitudes. No changes could be detected after placebo administration. One week after the termination of the treatment, Snellen line acuity and pattern VEP amplitude were decreased to pretreatment levels. The transient effect of levodopa points to a long-term treatment with the substance. Our results should therefore encourage further long-term clinical trials investigating the therapeutic potential of levodopa in amblyopia.