Effects of repeated intra-silicone oil injections of methotrexate on proliferative vitreoretinopathy grade C: a multicenter randomized controlled trial.

In this randomized controlled trial, we assessed the effects of three consecutive intra-silicone oil (SO) injections of methotrexate (MTX) on the outcomes of surgery for proliferative vitreoretinopathy grade C (PVR-C). Seventy-four eyes of 74 patients with PVR-C were included. Of these, 37 eyes were assigned to the MTX group and 37 eyes to the control group. Fourteen patients failed to comply with the 6-month follow-up period. All eyes underwent vitrectomy and SO injection. In the MTX group, 250 µg MTX was injected into the SO after surgery and at weeks 3 and 6 postoperatively. The primary outcome was the retinal reattachment rate at 6 months. The secondary outcomes included limited PVR recurrence and adverse events. Retinal reattachment was achieved in 22 eyes (73.3%) in the MTX group and 23 eyes (76.7%) in the control group (difference: -3.4%, 95% CI: -25.2-18.5%). Limited PVR recurrence was observed in one eye (4.5%) in the MTX group versus nine eyes (39.1%) in the control group at 6 months (P = 0.01). No adverse effects were observed. Adjunctive treatment with three consecutive applications of intra-SO MTX did not reveal a significant effect on the retinal re-detachment rate but could statistically significantly reduce limited PVR recurrence.Trial registration: http//ClinicalTrials.gov NCT04482543, 22/07/2020.