Study: NCT02706977

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: Low Dose Sinemet CR
Description: Sinemet CR (25 mg carbidopa/100 mg levodopa) will be taken by mouth twice daily for two weeks.

Intervention type: DRUG
Group type: EXPERIMENTAL
Intervention: High Dose Sinemet CR
Description: Sinemet CR (50 mg carbidopa/200 mg levodopa) will be taken by mouth twice daily for two weeks.

Intervention type: DEVICE
Group type: OTHER
Intervention: RETeval Electroretinogram (ERG) Testing
Description: ERG testing consists of sitting in the dark for 15 minutes. During the procedure, participants will have a single-use adhesive sensor strip placed on the skin near the eye. A hand-held device, called the RETeval, will be placed in front of the eye and a series of flashes and flickering lights presented. The light intensity level is typically not uncomfortable. When right eye imaging is complete, the procedure will be repeated on the left eye. Both eyes will be evaluated in less than 5 minutes for most participants. Electroretinogram (ERG) testing will be completed at baseline, day 1, week 2, and week 4.

Intervention type: DEVICE
Group type: EXPERIMENTAL
Intervention: RETeval Electroretinogram (ERG) Testing
Description: ERG testing consists of sitting in the dark for 15 minutes. During the procedure, participants will have a single-use adhesive sensor strip placed on the skin near the eye. A hand-held device, called the RETeval, will be placed in front of the eye and a series of flashes and flickering lights presented. The light intensity level is typically not uncomfortable. When right eye imaging is complete, the procedure will be repeated on the left eye. Both eyes will be evaluated in less than 5 minutes for most participants. Electroretinogram (ERG) testing will be completed at baseline, day 1, week 2, and week 4.

Intervention type: DEVICE
Group type: EXPERIMENTAL
Intervention: RETeval Electroretinogram (ERG) Testing
Description: ERG testing consists of sitting in the dark for 15 minutes. During the procedure, participants will have a single-use adhesive sensor strip placed on the skin near the eye. A hand-held device, called the RETeval, will be placed in front of the eye and a series of flashes and flickering lights presented. The light intensity level is typically not uncomfortable. When right eye imaging is complete, the procedure will be repeated on the left eye. Both eyes will be evaluated in less than 5 minutes for most participants. Electroretinogram (ERG) testing will be completed at baseline, day 1, week 2, and week 4.

Intervention type: DEVICE
Group type: OTHER
Intervention: RETeval Electroretinogram (ERG) Testing
Description: ERG testing consists of sitting in the dark for 15 minutes. During the procedure, participants will have a single-use adhesive sensor strip placed on the skin near the eye. A hand-held device, called the RETeval, will be placed in front of the eye and a series of flashes and flickering lights presented. The light intensity level is typically not uncomfortable. When right eye imaging is complete, the procedure will be repeated on the left eye. Both eyes will be evaluated in less than 5 minutes for most participants. Electroretinogram (ERG) testing will be completed at baseline, day 1, week 2, and week 4.

Intervention type: OTHER
Group type: OTHER
Intervention: Contrast Sensitivity Testing
Description: Contrast sensitivity testing consists of looking at a series of moving lines on a tablet device. The lines will change from white to grey to black. Participants will be asked to determine when they can no longer distinguish between the lines. Contrast sensitivity testing will be completed at baseline, day 1, week 2, and week 4.

Intervention type: OTHER
Group type: EXPERIMENTAL
Intervention: Contrast Sensitivity Testing
Description: Contrast sensitivity testing consists of looking at a series of moving lines on a tablet device. The lines will change from white to grey to black. Participants will be asked to determine when they can no longer distinguish between the lines. Contrast sensitivity testing will be completed at baseline, day 1, week 2, and week 4.

Intervention type: OTHER
Group type: EXPERIMENTAL
Intervention: Contrast Sensitivity Testing
Description: Contrast sensitivity testing consists of looking at a series of moving lines on a tablet device. The lines will change from white to grey to black. Participants will be asked to determine when they can no longer distinguish between the lines. Contrast sensitivity testing will be completed at baseline, day 1, week 2, and week 4.

Intervention type: OTHER
Group type: OTHER
Intervention: Contrast Sensitivity Testing
Description: Contrast sensitivity testing consists of looking at a series of moving lines on a tablet device. The lines will change from white to grey to black. Participants will be asked to determine when they can no longer distinguish between the lines. Contrast sensitivity testing will be completed at baseline, day 1, week 2, and week 4.

Intervention type: OTHER
Group type: OTHER
Intervention: Visual Acuity Testing
Description: Participants will be asked to look at an eye chart with letters or symbols that become smaller as they move from top to bottom of the chart. Visual acuity testing will be completed at baseline, day 1, week 2, and week 4.

Intervention type: OTHER
Group type: EXPERIMENTAL
Intervention: Visual Acuity Testing
Description: Participants will be asked to look at an eye chart with letters or symbols that become smaller as they move from top to bottom of the chart. Visual acuity testing will be completed at baseline, day 1, week 2, and week 4.

Intervention type: OTHER
Group type: EXPERIMENTAL
Intervention: Visual Acuity Testing
Description: Participants will be asked to look at an eye chart with letters or symbols that become smaller as they move from top to bottom of the chart. Visual acuity testing will be completed at baseline, day 1, week 2, and week 4.

Intervention type: OTHER
Group type: OTHER
Intervention: Visual Acuity Testing
Description: Participants will be asked to look at an eye chart with letters or symbols that become smaller as they move from top to bottom of the chart. Visual acuity testing will be completed at baseline, day 1, week 2, and week 4.