Differential distribution of fibrovascular proliferative membranes in 25-gauge vitrectomy for proliferative diabetic retinopathy.

Aim: To analyze the distribution of fibrovascular proliferative membranes (FVPMs) in proliferative diabetic retinopathy (PDR) patients that treated with pars plana vitrectomy (PPV), and to evaluate the outcomes separately.

Methods: This was a retrospective and cross-sectional study. Consecutive 25-gauge (25-G) PPV cases operated for PDR from May 2018 to April 2020. According to the FVPMs images outlined after operations, subjects were assigned into three groups: arcade type group, juxtapapillary type group, and central type group. All patients were followed up for over one year. General characteristics, operation-related variables, postoperative parameters and complications were recorded.

Results: Among 103 eyes recruited, the FVPMs distribution of nasotemporal and inferiosuperioral was significantly different (both P<0.01), with 95 (92.23%) FVPMs located in the nasal quadrants, and 74 (71.84%) in the inferior. The eyes with a central FVPM required the longest operation time, with silicon oil used in most patients, generally combined with tractional retinal detachment (RD) and rhegmatogenous RD, the worst postoperative best-corrected visual acuity (BCVA) and the highest rates of recurrent RD (all P<0.05). FVPM type, age of onset diabetes mellitus, preoperative BCVA, and combined with tractional RD and rhegmatogenous RD were significantly associated with BCVA improvement (all P<0.05). Compared with the central type group, the arcade type group had higher rates of BCVA improvement.

Conclusion: FVPMs are more commonly found in the nasal and inferior mid-peripheral retina in addition to the area of arcade vessels. Performing 25-G PPV for treating PDR eyes with central FVPM have relatively worse prognosis.