09/10/2025
At the 25th EURETINA Congress ( September 4–7, 2025), I was eagerly on the lookout for more studies related to circadian biology and how our light environment can affect vision, particularly for age-related macular degeneration (AMD). There were numerous presentations on photobiomodulation (PBM) and one very interesting study on vitamin D supplementation.
Photobiomodulation was approved in Europe in 2018 and excitingly, recently gained FDA authorization in the USA in January 2025 for dry AMD treatment. There is no news yet on when it will come to Australia.
The LIGHTSITE IIIB Trial showcased 4.5 years of PBM therapy using LumiThera’s Valeda Light Delivery System. This non-invasive treatment, involving brief light exposures of red light (590–850 nm wavelengths), improved visual acuity by +5.2 letters and reduced drusen growth by 18% in patients with intermediate dry AMD, compared to worsening vision in untreated controls. With no serious side effects, PBM is an exciting development.
The VITAMIN-D-AMD Trial found that high-dose vitamin D3 (40,000 IU weekly) along with AREDS2 supplements slowed drusen growth by 10% and boosted visual acuity by +3.8 letters in 18 months for AMD patients with low vitamin D levels. By reducing inflammation, vitamin D enhances standard therapies, addressing a common deficiency in older adults.
These studies, often conducted in far northern latitudes like Europe where sunlight is scarce for months, underscore the role of light exposure in retinal health. In Australia, we are fortunately much better able to harness these benefits naturally. Natural sunlight is rich in wavelengths akin to PBM and a natural source of vitamin D. It is still unclear whether PBM would be required in someone already getting a healthy dose of natural sunlight, so it seems to me a simple and low risk option to continue to encourage our patients to optimise their outdoor exercise to potentially slow AMD progression without clinic visits.
Dr Mark Donaldson
