Safety Profile of Slit-Lamp-Delivered Retinal Laser Photobiomodulation
Jack Ao, Glyn Chidlow, John P. M. Wood, Robert J. Casson
Abstract
Purpose: Photobiomodulation (PBM) refers to therapeutic irradiation of tissue with low-energy, 630- to 1000-nm wavelength light. An increasing body of evidence supports a beneficial effect of PBM in retinal disorders. To date, most studies have utilized light-emitting diode irradiation sources. Slit-lamp-mounted retinal lasers produce a coherent beam that can be delivered with precisely defined dosages and predetermined target area; however, the use of retinal lasers raises safety concerns that warrant investigation prior to clinical application. In this study, we determined safe dosages of laser-delivered PBM to the retina. Methods: A custom-designed, slit-lamp-delivered, 670-nm, red/near-infrared laser was used to administer a range of irradiances to healthy pigmented and non-pigmented rat retinas. The effects of PBM on various functional and structural parameters of the retina were evaluated utilizing a combination of electroretinography, Spectral Domain Optical Coherence (SD-OCT), fluorescein angiography, histology and immunohistochemistry. Results: displayed very localized photoreceptor damage in the peripapillary region, typically adjacent to the optic nerve head. Conclusions: irradiance; therefore, caution should be exercised in the dosage of laser-delivered PBM administered to pigmented retinas. Translational Relevance: This study provides important data necessary for clinical translation of laser-delivered PBM for retinal diseases.