Melatonin is a hormone in the body that plays a role in sleep, and its production in the brain is connected to time of day. More is produced when it is dark, and less is produced when it is light. Melatonin production also declines with age.¹

In addition to the body’s own production, melatonin is available as a supplement, typically as an oral tablet or capsule. People commonly use it for insomnia and other sleep disorders or for jet lag, and it has some proven efficacy for circadian rhythm sleep disorders in the blind.² A perhaps lesser-known use is its antioxidant and anti-inflammatory properties that have been shown to oppose several processes in age-related macular degeneration (AMD).^1,2 Recently, a research team sought to determine the association between melatonin use and the development and progression of AMD.²

This retrospective cohort study accessed data from TriNetX, a national database of de-identified electronic medical records. The study used data from both inpatient and outpatient health care organizations across the United States between December 4, 2023, and March 19, 2024. Patients aged 50 years or older, 60 years or older, and 70 years or older were organized into an AMD-naïve group and a non-neovascular (dry) AMD group. More than 120,000 people aged 50 or older with no history of AMD were included in the study, along with 65,000 dry AMD patients. Participants were queried for instances of melatonin medication codes between November 14, 2008 and November 14, 2023, and classified into a melatonin group or a control group accordingly.² The investigators performed propensity score matching (PSM) to match the cohorts based on demographic variables, comorbidities and non-melatonin hypnotic medication use.²

After PSM, the researchers compared the melatonin and the control cohorts to evaluate the risk ratios of having an outcome, defined as a new diagnosis of any AMD for the AMD-naïve group and progression to neovascular AMD for the dry AMD group.²

The results showed that taking melatonin was associated with a decreased risk of developing AMD. Likewise, among patients with pre-existing dry AMD, melatonin supplementation was negatively associated with the rate of progression to neovascular AMD.2 Although lifestyle factors may have influenced this association, these findings provide a basis for further study on the potential role of melatonin as a preventive therapy against AMD development and progression.

The authors pointed out that additional research is needed to validate the results, because other factors (such as smoking or access to health care) could play a part in the disease.² Still, other large cohorts could confirm these results if they are done in a way that controls for cigarette smoking and systemic risk factors (e.g., obesity and cardiovascular disease).

Although there is not enough information yet to classify melatonin as an official AMD treatment, the study results are promising. They are also exciting because melatonin is widely accessible and could easily be implemented if it is found to be effective. 

Reference(s):

1. Andersen LPH, Gögenur I, Rosenberg J, Reiter RJ. The safety of melatonin in humans. Clin Drug Investig. 2016 Mar;36(3):169-175. doi:10.1007/s40261-015-0368-5
2. Jeong H, Shaia JK, Markle JC, Talcott KE, Singh RP. Melatonin and risk of age-related macular degeneration. JAMA Ophthalmol. 2024 Jul;142(7):648-654. doi:10.1001/jamaophthalmol.2024.1822 

Joseph J. Pizzimenti, OD, FAAO, is a part-time faculty member at the Rosenberg School of Optometry at the University of the Incarnate Word in San Antonio, Texas. Dr. Pizzimenti graduated from the Illinois College of Optometry and completed a residency in Rehabilitative Optometry and Ocular Disease at the University of Houston. He is a Fellow of both the American Academy of Optometry (AAO) and the Optometric Retina Society (ORS), serving as ORS President from 2012 to 2014. A long-time optometric educator, Dr. Pizzimenti is a frequent author and speaker on posterior segment disease. Financial Disclosures: Dr. Pizzimenti has received honoraria and consulting fees from EyePromise, Zeiss and Notal Vision.