Cone Rescue with Laser Photobiomodulation in Murine and Human Retinal Dystrophy

Retinitis pigmentosa (RP) encompasses a genetically diverse group of blinding inherited retinal diseases. In most subtypes the gene defect is expressed in the rod photoreceptors, yet in many affected individuals the cone photoreceptors undergo secondary degeneration, leading to loss of the remaining central vision. There is evidence that bioenergetic and oxidative stress are involved in this secondary cone loss. Photobiomodulation (PBM) uses low energy light in the far red or near-infrared spectrum to manipulate cellular activity. We have used a novel slit lamp-mounted retinal PBM laser to deliver precise energy levels to targeted retina. We showed that PBM laser attenuates oxidative and bioenergetic stress-induced photoreceptor loss in vitro and rescues cones in the rd1 murine model of RP. In a phase I trial (ACTRN12618000651280), foveal laser treatment was safe in humans with RP and temporarily recovered, on average, 5 letters of visual acuity.