Does levodopa improve vision in albinism? Results of a randomized, controlled clinical trial.

Abstract

BACKGROUND:

Dopamine is an intermediate product in the biosynthesis of melanin pigment, which is absent or reduced in albinism. Animal research has shown that supplying a precursor to dopamine, levodopa, may improve visual acuity in albinism by enhancing neural networks. This study examines the safety and effectiveness of levodopa on best-corrected visual acuity in human subjects with albinism.

DESIGN:

Prospective, randomized, placebo-controlled, double-masked clinical trial conducted at the University of Minnesota.

PARTICIPANTS:

Forty-five subjects with albinism.

METHODS:

Subjects with albinism were randomly assigned to one of three treatment arms: levodopa 0.76 mg/kg with 25% carbidopa, levodopa 0.51 mg/kg with 25% carbidopa, or placebo and followed for 20 weeks, with best-corrected visual acuity measured at enrollment, and at weeks 5, 10, 15, and 20 after enrollment. Side-effects were recorded with a symptom survey. Blood was drawn for genotyping.

MAIN OUTCOME MEASURES:

Side-effects and best-corrected visual acuity 20 weeks after enrolment.

RESULTS:

All subjects had at least one mutation found in a gene known to cause albinism. Mean age was 14.5 years (range: 3.5 to 57.8 years). Follow up was 100% and compliance was good. Minor side-effects were reported; there were no serious adverse events. There was no statistically significant improvement in best-corrected visual acuity after 20 weeks with either dose of levodopa.

CONCLUSIONS:

Levodopa, in the doses used in this trial and for the time course of administration, did not improve visual acuity in subjects with albinism.

• Authors: C Gail Summers, John E Connett, Ann M Holleschau, Jennifer L Anderson, Inge De Becker, Brian S McKay, Murray H Brilliant
• Journal: Clinical & experimental ophthalmology (Clin Exp Ophthalmol) Vol. 42 Issue 8 Pg. 713-21 (Nov 2014) ISSN: 1442-9071 [Electronic] Australia
• PMID: 24641678 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 Royal Australian and New Zealand College of Ophthalmologists.

Chemical References

• Dopamine Agents
• Levodopa

Topics

• Administration, Oral
• Adolescent
• Adult
• Albinism, Oculocutaneous (drug therapy, genetics, physiopathology)
• Child
• Child, Preschool
• Dopamine Agents (adverse effects, therapeutic use)
• Double-Blind Method
• Female
• Humans
• Levodopa (adverse effects, therapeutic use)
• Male
• Middle Aged
• Prospective Studies
• Visual Acuity (drug effects, physiology)