Pilot randomized trial of a nanopulse retinal laser versus conventional photocoagulation for the treatment of diabetic macular oedema

Background: To assess the efficacy of a new nanopulse laser, retinal regeneration therapy for the treatment of diabetic macular oedema. Design: Randomized, non-inferiority, trial. Participants: 20 eyes of 17 subjects in the retinal regeneration therapy group and 18 eyes of 14 subjects in the conventional group were analysed. Methods: The treatment group received retinal regeneration therapy laser, and the control group received photocoagulation. Main Outcome Measures: The primary outcome was the optical coherence tomography-measured change in central retinal thickness at 6 months. A secondary outcome was the change in logarithm of minimum angle of resolution visual acuity at 6 months. Non-inferiority required the one-sided 95% confidence interval of the mean retinal thickness reduction after retinal regeneration therapy to be within 35 mm of the reduction after control laser. Results: When outliers were included in the dataset, the difference in retinal thickness reduction by analysis of covariance was 10.9 (standard deviation 17.6) mm in favour of the control laser. The difference between groups in retinal thickness reduction was 40.8 mm. If two extreme outliers were excluded, the difference was 5.6 (standard deviation 14.2) mm in favour of the retinal regeneration therapy laser, and the D optical coherence tomography was 18.5 mm. The visual acuity difference between groups was 0.059, meeting non-inferiority requirements. Conclusions: Although retinal thickness reduction was not unambiguously non-inferior, in the short-term, retinal regeneration therapy approximates the clinical efficacy of conventional photocoagulation, stabilizing visual acuity and providing motivation for larger trials assessing retinal regeneration therapy.