Molecular Mechanisms of Photobiomodulation in Retinal Diseases: Cytochrome c Oxidase, Mitochondrial Bioenergetics and Cytoprotective Signalling.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing molecular mechanisms and clinical trial findings without systematic review methodology
PubMed 42449957 · doi:10.3390/ijms27135683
What was done
This narrative review synthesized preclinical and clinical evidence on the molecular mechanisms of photobiomodulation (PBM) across the 590–950 nm range in retinal diseases. It summarized cytochrome c oxidase activation, downstream antioxidant and anti-inflammatory signaling, wavelength-specific actions, circadian interactions, and clinical outcomes across dry age-related macular degeneration (AMD), retinitis pigmentosa, central serous chorioretinopathy, and childhood myopia.
What was found
The abstract reports no numerical findings or effect sizes. Qualitatively, photon absorption by cytochrome c oxidase dissociates nitric oxide, restores proton-motive force, increases ATP synthesis, and activates Nrf2-driven antioxidant enzymes while suppressing NF-κB and NLRP3 inflammasomes. It notes that multiwavelength PBM (590/660/850 nm) showed best-corrected visual acuity improvements and reduced geographic atrophy incidence over 24+ months in randomized trials for dry AMD, whereas evidence for other retinal indications remains limited.
Why it matters
The review provides a comprehensive mechanistic framework linking photon absorption at mitochondrial complex IV to cellular survival cascades, while identifying chronotherapy as an emerging hypothesis to optimize retinal light therapy.
Limits
As a narrative review, the paper presents no new empirical data and did not use systematic search or meta-analytic methods. Clinical evidence is uneven across indications, remaining small and short-term for conditions outside non-exudative AMD, and proposed time-of-day circadian benefits remain an unconfirmed hypothesis.