The first study found that 3-4 minutes of application of red light at 670nm daily for 8 months inhibited early stage diabetic retinopathy in mice https://pubmed.ncbi.nlm.nih.gov/29167189/
This recent study found that it also worked well with humans – 670nm daily for 20 weeks. ” significantly inhibit the degenerative change of diabetic retinal vessels, and PBM is likely to produce its beneficial effects on the retina through promoting the migration of bone marrow stem cells to circulation and diabetic retinal tissue.” https://pubmed.ncbi.nlm.nih.gov/39716680/