Photobiomodulation protects the retina from light-induced photoreceptor degeneration

Rizalyn Albarracin, Janis Eells, Krisztina Valter*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    114 Citations (Scopus)


    Purpose. In this study, the hypothesis that near-infrared (NIR) light treatment (photobiomodulation) attenuates bright-light damage in the albino rat retina was tested. Methods. Young adult Sprague-Dawley (SD) albino rats were raised in dim (5 lux), cyclic light and then exposed to bright (1000 lux), continuous light for 24 hours. The animals were treated with 670-nm light (9 J/cm 2) in an LED array before, during, or after exposure to light. The retinas were examined for function, structural changes, cell loss, and markers of stress and inflammation at 1 week and 1 month after exposure to damaging white light. Results. Bright light caused photoreceptor-specific cell death in control retinas. Significant upregulation of stress and neuroprotective factors and the presence of activated microglia were also noted after light-induced damage. Photobiomodulation profoundly attenuated histopathologic alterations in all three treatment groups. NIR treatment also abolished microglial invasion of the retina and significantly reduced the presence of stress and neuroprotectant molecules. Bright-light-induced reductions in photoreceptor function were significantly ameliorated by photobiomodulation in animals treated before and during exposure to damaging light. Photoreceptor function was initially reduced in animals treated after bright-light-induced damage, but recovered by 1 month after exposure. Conclusions. NIR photobiomodulation is protective against bright-light-induced retinal degeneration, even when NIR treatment is applied after exposure to light. This protective effect appears to involve a reduction of cell death and inflammation. Photobiomodulation has the potential to become an important treatment modality for the prevention or treatment of light-induced stress in the retina. More generally, it could be beneficial in the prevention and treatment of retinal conditions involving inflammatory mechanisms.

    Original languageEnglish
    Pages (from-to)3582-3592
    Number of pages11
    JournalInvestigative Ophthalmology and Visual Science
    Issue number6
    Publication statusPublished - May 2011


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