Photobiomodulation therapy as a new hope therapy for retinitis pigmentosa: a systematic review

Abstract

Retinitis pigmentosa is one of the leading causes of hereditary blindness in developed countries and unfortunately there is currently no cure. Photobiomodulation therapy can penetrate the retina and optic nerve and restore the function of damaged mitochondria as an intracellular target. This study is proposed to review and analyze photobiomodulation as a strategy that has the potential to be a new hope therapy and non-invasive treatment for retinitis pigmentosa in the long term. PubMed® and Google Scholar were used to perform a systematic review of photobiomodulation as a therapy for retinitis pigmentosa. Using PRISMA 2020 Guidelines, we include seven studies in this review. The inclusion criteria for each study were as follows: the study documented the use of photobiomodulation therapy for retinitis pigmentosa, was conducted in human eyes or animals' eye, its full text was in English, and it published in the last 10 years. We anticipated that most studies would be experimental design, we evaluated the quality of eligible studies using relevant items from the ROBINS-I, which is the recommended tool to evaluate experimental study. There is a clinical improvement in visual acuity and visual fields. Further eye examination showed functional and outer nuclear layer preservation, decline waveforms of electroretinogram slower than control, disruption of retinal pigment epithelium, and preserved photoreceptor nuclei twice thicker than control (p < 0.05). Photobiomodulation also increases retinal mitochondrial function and maintains mitochondrial redox state, revealing significant recovery of photoreceptors' cell function. Photobiomodulation showed significant change in clinical improvement, mitochondrial repair, and retinal layer thickening; thus, photobiomodulation can be a new hope for therapeutic strategies for retinitis pigmentosa. Several studies only have a few participants, so it does not provide a long-term outcome in retinitis pigmentosa.