NCT07748715Not yet recruiting
Brain Dopamine Biomarker
Blue Color Processing in the Eye as a Biomarker of Brain Dopamine
Source: ClinicalTrials.gov · Last updated 12 Aug 2026
Brief summary (registry, in English)
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.
- Status (registry)
- Not yet recruiting
- Study type
- Observational
- Enrollment
- 50 (estimated)
- First submitted
- 31 Jul 2026
- Start date
- 1 Oct 2026
- Primary completion date
- 30 Sept 2027
- Lead sponsor
- University of South Florida
- Diseases
- Parkinson disease
- NCT number
- NCT07748715
What you commit to
- Study type: Observational
- Planned participants: 50
- From 1 Oct 2026 to the primary completion date, 30 Sept 2027
- No sites listed in no country
- Visits and tests: ask the trial team, the registry does not list them
Built from the registry fields of ClinicalTrials.gov. It describes the study, not your situation.
Who cannot take part
Copied verbatim from ClinicalTrials.gov and grouped by topic. Only the trial team decides who can take part.
Prior treatment
- Current use of antipsychotics, stimulants, or other medications known to affect central dopaminergic transmission
- Recent ocular surgery
- (non-PD subjects) a pre-screening survey will assess medication use and neurological history
- Ocular surgery within the past three months
- Use of medications known to affect retinal electrophysiology (e.g., chronic hydroxychloroquine, vigabatrin, deferoxamine, or isotretinoin)
Other illness
- Individuals with a history of photosensitive epilepsy or seizure activity triggered by visual stimuli
- History of photosensitive epilepsy or visually triggered seizures (especially relevant given the use of bright visual stimuli and potential flicker paradigms)
Age
- 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.
Other
- Any movement, strength, or balance assessments that may pose a potential risk for injury
- Pregnancy
- Phenylketonuria
- (PD participants) not cognitively intact and not able to consent for themselves
- Individuals with congenital color vision deficiencies, particularly tritan-spectrum defects
Who the study is looking for
- Parkinson's subjects will have received physician verified diagnosis of the disease and be on a dopaminergic medication for at least 3 months
Age in the registry: 18 years to - · Sex: All · Accepts healthy volunteers
This page is information, not medical advice. Discuss any trial with your doctor.