Proliferative diabetic retinopathy treated with intravitreal ranibizumab and photocoagulation directed at ischemic retinal areas—A randomized study

Purpose: To compare ETDRS panretinal laser photocoagulation (PRP) combined with intravitreal injection of ranibizumab (IVR) and photocoagulation targeted to ischemic retina (PIR) combined with IVR in patients with proliferative diabetic retinopathy (PDR). Methods: PDR patients were randomly assigned to treatment with either PRP + IVR or PIR + IVR. ETRDS Best-corrected visual acuity (BCVA) and central subfield thickness (CSFT) measured on optic-coherence tomography images (OCT-Heidelberg Spectralis) were recorded at baseline and every 4 weeks for one year. Fluorescein leakage area (FLA) from active new vessels was measured every 12 weeks. Full-field ERG was recorded by means of DTL electrodes, following ISCEV standard recommendations, at baseline and after 3 months. Results: Twenty-eight eyes completed the study period. At baseline, mean ± SE BCVA (logMAR) was 0.44 ± 0.07 and 0.37 ± 0.08 (P = 0.5030); CSFT (μm) was 324.0 ± 20.4 and 330.1 ± 22.1 (P = 0.8417); and FLA (mm²) was 16.10 ± 4.42 and 9.97 ± 1.83 (P = 0.2114) for PRP + IVR and PIR + IVR groups, respectively. There were no relevant changes on BCVA or CSFT, but a significant reduction for FLA was observed at all visits compared to baseline for both groups, with no differences between groups. ERG showed at baseline reduced dark-adapted amplitudes, and these changes were also significantly amplified after laser treatment. ROD b-wave amplitude was further reduced in 62 ± 6% for PRP + IVR and 59 ± 4% for group PIR + IVR, but with no between-groups significant difference (P = 0.9082). Conclusions: PIR + IVR or PRP + IVR are comparable strategies regarding FLA control in PDR and led to similar retinal function impairment, based on ERG changes up to one-year follow-up. Trial registration number: NCT03904056, date of registration 02/11/2019, retrospectively registered.