Microinvasive pars plana vitrectomy versus panretinal photocoagulation for severe non-proliferative diabetic retinopathy: a randomised controlled trial

PURPOSE: To evaluate the progression rate of severe non-proliferative diabetic retinopathy (sNPDR) in eyes treated with microinvasive pars plana vitrectomy (PPV) versus panretinal photocoagulation (PRP) over 12 months. METHODS: 55 eyes of 55 diabetic patients aged >18 years with sNPDR were randomised 1:1 to the PPV group (n=27) or the PRP group (n=28). Standard 25G PPV was performed by an experienced surgeon within 4 weeks of enrolment. Standard PRP was performed in three sessions within 4 weeks of enrolment. The primary outcome was the proportion of eyes progressed from sNPDR to proliferative diabetic retinopathy (PDR) over 12 months. RESULTS: A total of 27 participants (mean (SD) age, 61.19 (8.89) years; 16 male (59.3%)) in the PPV group and 28 participants (mean (SD) age, 60.50 (7.93) years; 11 male (39.3%)) in the PRP group were analysed. At 12 months, no patients in the PPV group progressed to PDR, compared with 2 of 28 patients (7.1%) in the PRP group (p=0.49). The mean (SD) change in total visual field point score was -16.70 (415.23) dB in the PPV group and -314.00 (404.59) dB in the PRP group (p=0.02). For the peripheral 60-4 test, the mean (SD) change was -11.39 (167.99) dB in the PPV group versus -207.05 (308.66) dB in the PRP group (p=0.02). CONCLUSIONS: In patients with sNPDR, PPV and PRP showed no significant difference in PDR progression during the 12-month follow-up, whereas the PPV group preserved better peripheral visual function. TRIAL REGISTRATION NUMBER: NCT04103671.