The purpose of this study is to evaluate the use of electroretinogram (ERG) using a novel handheld system, RETeval, and evaluate contrast sensitivity testing in detecting pre-clinical retinopathy on a tablet device.~Investigators also seek to assess if a medication called Sinemet™ CR can improve the electrical functions of the eye in participants with diabetes mellitus. This study will include a total of 45 participants; 30 with diabetes mellitus and 15 age-matched non-diabetic controls. Participants with diabetes mellitus and electroretinogram (ERG) delays will be randomized to a low or high dose Sinemet™ CT group.~Age-matched controls will not receive Sinemet Ct drug treatment.~The study involves four visits over the course of 4 weeks, each visit consisting of 2-3 hours. Visual testing will be performed at 1 day and 2 weeks following treatment. The drug treatment will be halted and testing repeated again after a 2 week wash-out period.
The purpose of this study is to evaluate the use of electroretinogram (ERG) using a novel handheld system, RETeval, and evaluate contrast sensitivity testing in detecting pre-clinical retinopathy on a tablet device.~Investigators also seek to assess if a medication called Sinemet™ CR can improve the electrical functions of the eye in participants with diabetes mellitus. This study will include a total of 45 participants; 30 with diabetes mellitus and 15 age-matched non-diabetic controls. Participants with diabetes mellitus and electroretinogram (ERG) delays will be randomized to a low or high dose Sinemet CR group.