The goal of proliferative diabetic retinopathy (PDR) treatment should not only be to prevent blindness but also to maintain visual acuity (VA) after vitrectomy. Researchers in Japan built a dataset of cases completely followed up two or four years after vitrectomy for PDR to pinpoint the factors that correlate with visual outcomes. These included no rubeosis iridis, no fibrovascular membrane, presence of vitreous hemorrhage (VH) and no reoperation.

The researchers retrospectively analyzed 128 eyes of 100 patients who underwent vitrectomy for PDR. Among them, 91 eyes from 70 patients were followed for four years. The team investigated factors related to postoperative VA of ≥20/40 and ≥20/30 after two and four years with logistic regression analysis.

The study demonstrated that the absence of rubeosis iridis and fibrovascular membrane before surgery correlated with ≥20/40 VA at two years postoperatively; whereas, the absence of rubeosis iridis and the presence of VH preoperatively correlated with ≥20/30 VA at two years post-op.

At four years post-op, the absence of preoperative fibrovascular membrane and reoperation correlated with ≥20/40 VA, and the absence of reoperation and rubeosis iridis and fibrovascular membrane preoperatively correlated with ≥20/30 VA. Also, an improvement in logMAR VA of >0.3 was found in 74.2% and 69.2% of patients at two and four years after surgery, respectively.

The researchers found that the distribution of VA at two years post-op had more significantly improved than that of preoperative VA. However, such distribution between two and four years post-op had no significant difference.

Those with recurrent VH, retinal detachment or neovascular glaucoma after primary vitrectomy for PDR underwent reoperation, which indicated that performing minimal activity after surgery for PDR is required to maintain VA from two to four years.

Since provision of treatment before the condition became severe and lack of treatment complications were associated with good post-op VA, the researchers concluded that optimal treatment timing at an early stage is vital for patients with PDR.

Nishi K, Nishitsuka K, Yamamoto T, et al. Factors correlated with visual outcomes at two and four years after vitreous surgery for proliferative diabetic retinopathy. PLOS One. January 14, 2021. [Epub ahead of print].