The Retina TL;DR with Dr. Weng: Unpacking photobiomodulation for dry AMD with Drs. Do, Lad, and Munk

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In this latest episode of The Retina TL;DR, powered by Modern Retina, host Christina Y. Weng, MD, MBA, FASRS, professor and the Alice R. McPherson Retina Research Foundation Chair in Ophthalmology at Baylor College of Medicine in Houston, Texas, welcomes Diana V. Do, MD; Eleonora (Nora) M. Lad, MD, PhD; and Marion R. Munk, MD, PhD—three co-authors of the LIGHTSITE III 13-month data publication¹—to discuss photobiomodulation (PBM) as the first minimally invasive FDA-authorized treatment for dry age-related macular degeneration (AMD) with visual acuity loss.

Do is professor of ophthalmology and vice chair of clinical affairs at the Byers Eye Institute at Stanford University School of Medicine, Palo Alto, California; Lad is vice chair of ophthalmology clinical research at Duke University Medical Center, Durham, North Carolina; and Munk is chief scientific officer and head of research at Gutblick Practise Group, Switzerland, and professor of ophthalmology at Inselspital, University Hospital Bern, Bern, Switzerland.

When asked to provide a “TL;DR” (“too long; didn’t read”) on behalf of the group, Lad summarized: "Photobiomodulation is the first minimally invasive FDA-approved treatment for dry AMD with visual acuity loss, and it demonstrated an excellent safety profile and improvement in both clinical and anatomical outcomes in clinical trials."

What is photobiomodulation?

Munk explained that PBM is a low-level light therapy using multiple wavelengths to improve cellular function. The multiwavelength light delivery system (Valeda; Alcon) received FDA clearance in November 2024 as the first CE-marked and FDA-cleared ophthalmic PBM platform for dry AMD.² It delivers red, yellow, and near-infrared wavelengths targeting mitochondrial cytochrome c oxidase, enhancing adenosine triphosphate (ATP) production and reducing oxidative stress, inflammation, and complement activation in the retina.³

LIGHTSITE III trial design and results

Do outlined the pivotal LIGHTSITE III trial—a randomized, controlled study enrolling eyes with intermediate dry AMD without choroidal neovascularization or center-involving geographic atrophy at baseline. Patients were randomly assigned to active PBM or an active sham with reduced light levels and one wavelength removed. Active PBM improved vision by a mean of approximately 6 letters versus approximately 3 letters in the sham group—a statistically significant difference sustained through 24 months.¹ (Update: LIGHTSITE III 24-month data have since been published.⁴)

Addressing community questions

Lad noted the sham group experienced worsening due to disease progression and GA conversion, whereas the PBM group showed a mean gain of 6.3 letters maintained at 24 months with retreatment at 4-month intervals.¹ On cataracts, Munk clarified that the PBM arm actually carried higher baseline cataract burden—41% pseudophakic versus 67% in sham—and full cataract data will appear in the forthcoming 24-month publication.¹ On the slightly higher rate of neovascular AMD in the PBM arm, Do attributed this to a baseline imbalance in high-risk eyes rather than a treatment signal.^1,4

Potential disease-modifying effects

LIGHTSITE III showed a significantly lower rate of new-onset GA in the PBM arm—1.1% versus 9.8% in sham—suggesting possible disease-modifying effects beyond visual acuity improvement.^1,4

Practice implementation

The novel PBM platform is priced at approximately $70,000. (Note: Alcon completed its acquisition of LumiThera on September 3, 2025; the Valeda system is now commercialized under Alcon.²) Treatment consists of nine sessions over approximately one month, repeated quarterly, with each session requiring less than 5 to 10 minutes and no dilation.¹ Some insurance carriers may cover the therapy; specialists are advised to consult their individual state medical boards regarding who may administer treatment.

Chronic therapy and the extension study

The LIGHTSITE IIIB extension study showed that following a roughly 20-month treatment gap, patients who resumed PBM regained more than 5 letters—returning to their prior level of improvement—while those originally in the sham arm who crossed over showed stabilization but limited recovery.^5-9 Sustained benefit was observed across approximately 54 months.^6,7

Looking ahead

Lad noted that although PBM addresses an important unmet need, the field still requires disease-modifying cures capable of reversing functional and structural manifestations.

Christina Y. Weng, MD, MBA, FASRS, is professor and the Alice R. McPherson Retina Research Foundation Chair in Ophthalmology, and fellowship program director, vitreoretinal diseases and surgery with Baylor College of Medicine in Houston, Texas. Weng is a consultant for Alcon.

Diana V. Do, MD, is professor of ophthalmology and vice chair of clinical affairs at the Byers Eye Institute at Stanford University School of Medicine, Palo Alto, California. Do receives research funding from LumiThera and is a consultant to LumiThera and Alcon.

Eleonora (Nora) M. Lad, MD, PhD, is professor of ophthalmology and vice chair of ophthalmology clinical research at Duke University Medical Center, Durham, North Carolina. Lad receives research funding from LumiThera and is a consultant to LumiThera and Alcon.

Marion R. Munk, MD, PhD, is chief scientific officer and head of research at Gutblick Practise Group, Switzerland, and professor of ophthalmology at Inselspital, University Hospital Bern, Bern, Switzerland. Munk is a consultant for LumiThera and Alcon.

REFERENCES

1. Boyer D, Hu A, Warrow D, et al. LIGHTSITE III: 13-month efficacy and safety evaluation of multiwavelength photobiomodulation in nonexudative (dry) age-related macular degeneration using the Lumithera Valeda Light Delivery System. Retina. 2024;44(3):487-497. doi:10.1097/IAE.0000000000003980

2. Alcon completes acquisition of LumiThera. News release. Alcon. September 3, 2025. Accessed April 14, 2026.

3. Rosen RB. Photobiomodulation: innovation on the horizon for dry AMD. Retina Today. Published May/June 2024. Accessed April 14, 2026. https://retinatoday.com/articles/2024-may-june/photobiomodulation-innovation-on-the-horizon-for-dry-amd

4. Jaffe GJ, Boyer D, Hu A, et al. Long-term efficacy and safety of photobiomodulation in dry age-related macular degeneration (LIGHTSITE III: 24-month analysis). Retina. doi:10.1097/IAE.0000000000004822

5. Asanad S. Photobiomodulation therapy delays dry AMD progression. Retinal Physician. Published March 1, 2025. Accessed April 14, 2026. https://www.retinalphysician.com/issues/2025/march/photobiomodulation-therapy-delays-dry-amd-progression/

6. LumiThera's LIGHTSITE IIIB extension trial topline results show extended vision improvement in dry AMD subjects. News release. LumiThera. May 8, 2025. Accessed April 14, 2026. https://lumithera.com/news/lumitheras-lightsite-iiib-extension-trial-topline-results-show-extended-vision-improvement-in-dry-amd-subjects/

7. Do DV, Nguyen QD, Rosen RB, et al. LIGHTSITE IIIB: an open-label, prospective, multi-center extension study to assess the long-term safety and efficacy of photobiomodulation in dry age-related macular degeneration [abstract]. Invest Ophthalmol Vis Sci. 2025;66(8):4589. Presented at: Association for Research in Vision and Ophthalmology Annual Meeting; May 4-8, 2025; Salt Lake City, UT.

8. Do D. ARVO 2025: update on the LIGHTSITE III study in AMD. Ophthalmology Times. Published May 15, 2025. Accessed April 14, 2026. https://www.ophthalmologytimes.com/view/arvo-2025-update-on-the-lightsite-iii-study-in-amd

9. Gallagher J. LIGHTSITE IIIB extends PBM evidence in dry AMD. Retinal Physician. Published July 31, 2025. Accessed April 14, 2026. https://www.retinalphysician.com/issues/2025/julyaugust/asrs15/