This study is investigating the optimal timing of using levodopa in reducing damage in the retina from diabetes mellitus. Adult subjects will be recruited from the Atlanta VA Eye clinic and randomized to one of four arms: placebo, levodopa every other day, levodopa daily, or levodopa twice daily. Each group include participants that will receive treatment for 6 months with eye exams and testing conducted at baseline, 3 month, and 6 month visits. Testing at the visits includes electroretinograms, fundus photography, optical coherence tomography with angiography, and HbA1c serology. Veterans will sign the consent, in-person prior to beginning study activities.
