Prognostic information for PRP-naive patients
Reviewed by Saruban Pasu

The Diabetic Retinopathy Study group demonstrated that pan retinal laser photocoagulation (PRP) reduces severe vision loss by up to 50% in cases of proliferative diabetic retinopathy (PDR). The authors of this current study aimed to provide information for laser naive patients regarding the risk of future vitrectomy based on clinical examination findings. A retrospective review was carried out on 374 eyes principally noting the date of initial PRP and dates / incidence of vitrectomy. Patients were divided into three groups: Group 1 (PDR alone) n=185, Group 2 (PDR and VH) n=160, Group 3 (PDR with neovascularisation of the iris [NVI], VH and traction, VH and fibrosis, or fibrosis alone) n=29. The percentage of eyes undergoing vitrectomy within one year was 9.73%, 26.9% and 37.9%, respectively. Within two years the percentage of eyes were 15.7%, 34.4% and 48.3%, respectively. Group 2 patients were 2.78 times and Group 3 were 3.54 times more likely than Group 1 patients to undergo vitrectomy within two years. Findings such as VH or fibrosis at initial PRP were found to be statistically significant in influencing the incidence of vitrectomy within two years. Patients not on insulin therapy were 1.74 times more likely to require vitrectomy within two years than those on insulin. This study provides quantitative and statistically significant evidence that diabetic patients with PDR receiving PRP have a 12.2% and 21.1% likelihood of undergoing a vitrectomy within the next one to two years, respectively. Patients who present with PDR with other clinical findings, such as VH, fibrosis, traction, and both VH and traction together, will have a much higher likelihood of requiring a vitrectomy within the next couple of years. 

Ocular findings at initial pan retinal photocoagulation for proliferative diabetic retinopathy predict the need for future pars plana vitrectomy.
Parikh R, Shah R, Vanhouten J, et al.
RETINA
2014;34(10):1997-2002.