Robert J. Casson, John Wood, Jack Ao, Jagjit Gilhotra, Shane Durkin, Weng Chan, Glyn Chidlow

Purpose: To investigate the effect of a novel slip lamp- delivered photobiomodulation (PBM) laser on cone res- cue in murine and human retinal dystrophy.

Methods: We assessed the effect of a prototype PBM 670 nm laser on retinal cells under oxidative stress and mitochondrial compromise and then investigated the effect of this laser treatment on cone survival in a murine model of retinitis pigmentosa (the rd1 mouse). We then conducted a phase I trial (ACTRN12618000651280) of this PBM laser in 2 cohorts of patients with advanced retinitis pigmentosa (n = 6 per group).

Results: PBM laser rescued photoreceptors in vitro and in the rd1 mice. Foveal laser treatment was safe in humans with retinitis pigmentosa and temporarily recovered, on average, five letters of visual acuity.

Conclusions: Slit lamp-delivered 670 nm retinal laser warrants further investigation as a therapy to attenuate secondary cone degeneration.