A recent study revealed that levodopa, a drug commonly used to treat Parkinson’s disease, is associated with a reduced likelihood of developing neovascular age-related macular degeneration (nAMD).

Age-Related Eye Disease Study 2 (AREDS2) vitamins are currently the only option for prevention of conversion from non-neovascular to neovascular AMD, but the study authors note this approach only reduces the relative risk by 25%. Their research, published in Ophthalmology Retina, focused on finding additional approaches to reduce neovascular AMD progression.

The study used the Vestrum Health Retina Database and the Merative MarketScan Research Databases to assess the relationship between levodopa (L-DOPA) use and nAMD risk. Diverse cohorts of 92,500 patients from the Vestrum database and 3.6 million patients from the Merative database were analyzed.

They described L-DOPA’s mechanism of action in nAMD: it acts on the retinal pigment epithelium to “increase the expression of pigment epithelial derived factor and decrease the expression of VEGF [vascular endothelial growth factor] and exosomes,” both of which are implicated in the pathogenesis of nAMD. They hypothesized that “local choroidal L-DOPA levels may be a modifiable risk factor for neovascular AMD.”

Not only did eyes treated with L-DOPA have a significantly lower burden of intravitreal injections, but patients consistently treated with L-DOPA also had lower progression rates from intermediate AMD to nAMD compared to non-treated groups. L-DOPA-treated eyes from the Vestrum database received fewer intravitreal injections at both year 1 and year 2 compared to non-exposed eyes, and, by year 5, L-DOPA exposure was associated with a 28% reduced risk of conversion to nAMD.

Further, higher doses of L-DOPA showed greater reductions in nAMD risk. Patients who received between 100–300 mg per day of L-DOPA had a 15% reduction in nAMD risk, while those receiving over 300 mg per day had a 23% reduction.

“Our data support a positive effect for L-DOPA to inhibit the conversion to neovascular AMD, which accounts for 90% of vision loss in AMD,” the researchers conclude. However, because the medication is primarily used with patients with Parkinson's disease, there is a risk of unexpected side effects, and the researchers note the need for a randomized, controlled clinical trial to follow up on this study.

A full list of author disclosures can be found in the published research.