Abstract
Photobiomodulation (PBM) refers to the beneficial effect produced from low-energy light irradiation on target cells or tissues. Increasing evidence in the literature suggests that PBM plays a positive role in the treatment of retinal diseases. However, there is great variation in the light sources and illumination parameters used in different studies, resulting in significantly different conclusions regarding PBM’s therapeutic effects. In addition, the mechanism by which PBM improves retinal function has not been fully elucidated. In this study, we conducted a narrative review of the published literature on PBM for treating retinal diseases and summarized the key illumination parameters used in PBM. Furthermore, we explored the potential molecular mechanisms of PBM at the retinal cellular level with the goal of providing evidence for the improved utilization of PBM in the treatment of retinal diseases.
Summary
The high metabolic features of the retina require high energy supply, and therefore, most retinal neurons contain a large number of mitochondria to produce sufficient ATP. However, when the mitochondrial function is compromised, it leads to oxidative-stress induced damage in the retina. Light irradiation via PBM can increase the rate of mitochondrial ATP production and suppress inflammatory responses in the retina, thus playing a positive therapeutic role in many retinal diseases. Red to near-infrared light wavelengths in the range of 635–680 nm and 810–830 nm are suitable for inducing PBM to treat retinal diseases, while a 670 nm red laser or LED light wavelength is the most reported light source wavelength in the literature for inducing PBM to treat retinal diseases. Irradiance and energy density are the two key parameters that need to be carefully controlled during PBM therapy. The stage of retinal disease progression is another factor that should be considered when adopting PBM to achieve the best clinical effects.
