Brain Dopamine Biomarker

Sponsor
University of South Florida
Study ID
NCT07748715
Status
Not Yet Recruiting

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Conditions

Eligibility Criteria

Sex
ALL
Age
18 Years - N/A
Healthy Volunteers
Accepted

Interventions

  • Levadopa/Carbidopa eyedrops — DRUG
    Topical levodopa/carbidopa eyedrops (1.4/0.34 microM) in a base of 0.1% w/v ascorbic acid and 0.001% w/v benzalkonium chloride dissolved in 1× phosphate-buffered saline.
  • Sham — OTHER
    The vehicle (control) solution will consist of 0.1% w/v ascorbic acid and 0.001% w/v benzalkonium chloride dissolved in 1× phosphate-buffered saline.
  • Levodopa/Carbidopa (Sinemet) — DRUG
    Parkinson's patients will self-administer their medication and measurements will be taken prior to and 15-30 minutes after self-administration.

Study Details

This study is being conducted at the Morsani College of Medicine to determine whether signals recorded from the eyes and brain can be used as a noninvasive way to monitor dopamine function. Approximately 50 adults (25 with Parkinson's disease and 25 without Parkinson's disease) will participate. Participants will undergo electroretinography (ERG) and electroencephalography (EEG), which are FDA-approved, noninvasive devices that measure electrical activity from the retina and brain using sensors placed on the skin around the eyes and scalp. Participants with Parkinson's disease will be tested before and after taking their prescribed Parkinson's medication (e.g., Sinemet® \[carbidopa/levodopa\]). Participants without Parkinson's disease will receive a single dose of compounded levodopa/carbidopa eye drops (an FDA-approved drug used in an unapproved ophthalmic formulation) in one eye and a placebo eye drop in the other eye. The placebo consists of the same vehicle solution without levodopa/carbidopa and contains 0.1% ascorbic acid, 0.001% benzalkonium chloride, and phosphate-buffered saline. Randomization will be used to determine which eye receives the levodopa/carbidopa eye drop and which eye receives the placebo. Researchers will compare measurements obtained before and after treatment to evaluate whether blue-light visual responses are associated with dopamine activity.

Key Dates

First listed
Aug 6, 2026
Start date
Oct 1, 2026
Status verified
Aug 2026
Primary completion
Sep 30, 2027
Completion
Sep 30, 2027

Study Design

Enrollment
50 participants (estimated)

Arms

  • Arm: Healthy controls
    Adults (18+ years) with no underlying eye conditions that would affect blue light transmission
  • Arm: Parkinsons
    As the Parkinson's patients self-administer dopaminergic medication, we will use this regular event of dopamine influx as a vehicle to measure changes in dopamine transmission in the eye.

Primary Outcome Measure

Electroretinography [ Time Frame: 2 measurements separated by 1 hour ]

Central Contacts

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