Vision Response to Dopamine Replacement

The purpose of the study is to evaluate and document physiologic and functional changes in visual performance and retinal function of patients diagnosed with albinism (a dopamine deficiency state) following a trial of oral Levodopa/carbidopa treatment.

In this study the investigators propose that the retina itself in albinism is deficient in dopamine, and vision improvement will occur as a result of improved retinal function in response to the deficient neurotransmitter dopamine. This study has a pretest-posttest design in order to determine if improvement in vision is in response to replacement of deficiency (dopamine). The electroretinography (ERG) testing and optical coherence tomography (OCT) will be critical determinants to confirm vision improvement as a result of improved retinal function, but are not primary outcome data. Main outcome measures will be collected at pre-treatment, 1 month, 3 months, and 4 months. Change in visual acuity as measured in logMAR by Snellen or sweep visual evoked potential (SVEP) after 3 months of treatment is the primary outcome. Patients include OCA1a patients, OCA1b, OCA2, and unclassified Oculocutaneous albinism (OCA). OCA1a patients clinically are known to have the worst vision, and physiologically have the lowest (or absent) levels of tyrosinase function (Dopamine Production). All patients will be treated with Levodopa/carbidopa 4mg/kg/day in three divided doses.

This study will have an intent to treat goal. Anyone that fits the inclusion criteria for the study will be entered and receive study drug.

Change in visual acuity from baseline to 3 months as measured in logMAR by Snellen or Sweep visual evoked potential (SVEP). logMar lower values equals better visual outcome.

Ancillary testing of visual/retinal function with contrast sensitivity testing. Contrast sensitivity testing measures how well the eyes can distinguish between finer and finer light increments compared to dark. This test is a chart with different capital letters organized in horizontal lines. The contrast decreases with each line. The person will move down the chart to determine the least level of contrast they can see.

Inclusion Criteria: clinical diagnosis of oculocutaneous albinism age over 3 and weight over 25 lbs. Exclusion Criteria: ocular only albinism ocular pathology other than albinism neurologic disease, history of myocardial infarction, history of clinical depression, pregnancy