PBM for Dry AMD: What Is Established and What Remains Open?

Background: A Specialist Dialogue in Bochum

In February 2026, the Association of Rhineland-Westphalian Ophthalmologists organized a dialogue session in Bochum to discuss the current status of photobiomodulation (PBM) for dry age-related macular degeneration (AMD). The central clinical question: Is the postulated mechanism sufficient to measurably influence function and progression?

The occasion was the growing international attention following the FDA authorization of the Valeda Light Delivery System – the first PBM device approved for AMD treatment in the United States. Dr. Georg Gerten, ophthalmologist from Cologne and MACULIGHT study investigator, summarized the current state of knowledge in a comprehensive status report for the Ophthalmologische Nachrichten (issue 04/2026).

His assessment: Between enthusiasm and methodologically sober classification, a differentiated view is needed. This article summarizes the key findings.

Why PBM? Mechanism and Evidence

Photobiomodulation describes the application of low-energy light in defined wavelength ranges to modulate cellular processes. The plausible biological approach is the absorption by intracellular photoacceptors, particularly cytochrome c oxidase, with downstream effects on mitochondrial function, ATP-dependent processes, and ROS signaling pathways. Especially for the metabolically highly active outer retina and the retinal pigment epithelium, which play a central role in the pathophysiology of AMD, this mechanism of action appears attractive.

However, plausibility is not the same as clinical benefit. The published evidence is extensive but heterogeneous: study populations (AMD stage, extent of geographic atrophy), endpoints (best-corrected visual acuity, contrast, low-luminance parameters), and physical parameters differ considerably. This makes direct comparisons difficult.

The pivotal approval study is the sham-controlled LIGHTSITE III study (NCT04065490) – a prospective, multicenter, randomized, double-masked design. In the 13-month analysis, the primary endpoint (BCVA) was statistically significantly achieved with an intergroup difference of 2.4 ETDRS letters. However, a small letter gain must be interpreted in a differentiated manner, as visual acuity and photoreceptor reserve do not correlate linearly.

Regulatory Classification: FDA, EU, and Germany

The Valeda Light Delivery System is an approved medical device and therapeutic procedure in both Europe and the USA. The FDA authorized the device based on the controlled study data from LIGHTSITE III. European institutions have also approved PBM treatment under the new Medical Device Regulation.

The German specialist societies, however, remain cautious: they recommend applying the procedure only within the framework of studies. This is not a rejection, but rather a call for further data before a broad recommendation can be made. The current position of the DOG, the Retinological Society, and the Professional Association of Ophthalmologists (BVA) from July 2025 explicitly states that PBM should currently only be used in clinical studies.

Why a Reassessment Is Imminent

The current evidence represents a snapshot. Several ongoing studies will provide new data in the medium term that could significantly change the assessment:

At the latest when the results of the MACULIGHT study are available, a reassessment of PBM should be carried out with a focus on patient selection, standardized protocols, and patient-relevant endpoints.

Safety Profile and Home Therapy Concept

In the sham-controlled data, side effects were reported rarely overall and described predominantly as mild and transient (e.g., temporary blurred vision). Neither phototoxic retinal damage nor a reliable signal for PBM-induced acceleration of atrophic progression was described. Based on the controlled data published to date, PBM thus shows an overall favorable safety and tolerability profile.

A central practical obstacle is adherence: weekly appointments over a long period are particularly difficult to achieve for elderly patients. The MACULIGHT study therefore investigates the concept of PBM home therapy over a period of twelve months. The study design is based on an intraindividual comparison between study eye and partner eye with sham treatment. Endpoints include BCVA under normal lighting, contrast vision, structural progression markers, and the transition to wet AMD.

The MACULIGHT study is being funded by the German Federal Ministry of Education and Research (BMBF) and is being conducted at five specialized centers in Germany. MACULIGHT Therapy → | Find a Doctor →

Conclusion: Out of the Experimental Stage

The status report's conclusion is clear: PBM has moved beyond the experimental stage through sham-controlled study data and FDA authorization. Whether a broad recommendation follows depends less on individual signals than on consistent reproducibility, patient-relevant endpoints, and practical feasibility.

Standardized protocols and home therapy studies could provide the decisive step from "evidence under study conditions" to real-world effectiveness. The MACULIGHT study is designed to deliver exactly these answers.

For patients with dry AMD, this means: PBM is a scientifically investigated, non-invasive approach that is being taken seriously internationally. However, it is not yet a standard therapy – the ongoing studies will determine whether and for whom PBM becomes a recommended treatment option.