Not Yet RecruitingNot Applicable

Brain Dopamine Biomarker

50 participantsStarted 2026-10-01

Plain-language summary

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.

Who can participate

Age range

18 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Parkinson's subjects will have received physician verified diagnosis of the disease and be on a dopaminergic medication for at least 3 months Exclusion Criteria: * Any movement, strength, or balance assessments that may pose a potential risk for injury * Individuals with a history of photosensitive epilepsy or seizure activity triggered by visual stimuli * Current use of antipsychotics, stimulants, or other medications known to affect central dopaminergic transmission * Pregnancy * Recent ocular surgery * Phenylketonuria * (PD participants) not cognitively intact and not able to consent for themselves * (non-PD subjects) a pre-screening survey will assess medication use and neurological history * Ophthalmologic or visual system conditions that may interfere with stimulus delivery or retinal function. These include significant cataract (defined as LOCS III ≥ NC2/NO2 or any media opacity that precludes adequate delivery of visual stimuli to the retina), active retinal or macular pathology (including age-related macular degeneration with significant drusen or geographic atrophy, diabetic retinopathy, retinal vein occlusion, or epiretinal membrane with foveal involvement), glaucoma, or any optic neuropathy. * Individuals with congenital color vision deficiencies, particularly tritan-spectrum defects * Ocular surgery within the past three months * Use of medications known to affect retinal electrophysiology (e.g., chronic hydroxychloroquine, vigabatrin, de…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Electroretinography

Timeframe: 2 measurements separated by 1 hour

Trial details

NCT IDNCT07748715

SponsorUniversity of South Florida

Sponsor typeOTHER

Study typeOBSERVATIONAL

Primary completion2027-09-30

Contact for this trial

Nathan D Schilaty, DC, PhD

813-974-1377 nschilaty@usf.edu

View on ClinicalTrials.gov More Parkinson Disease trials