Need for consensus building on peripheral avascular retina in retinopathy of prematurity

Dear Editor, The changing practices in treating retinopathy of prematurity (ROP) over the last two decades have resulted in the emerging question of whether peripheral avascular retina (PAR) in ROP is associated with an increased lifetime risk of rhegmatogenous retinal detachment (RRD). A high risk of development of peripheral lesions (>50%) and RRD (>38.6%) has been reported in untreated ROP eyes,[1] which suggested further prospective studies. A recent long-term study on anti-Vascular endothelial growth factor (anti VEGF) treated eyes has noted persisting PAR in 75% of eyes on angiogram but did not comment on the presence of peripheral lesions predisposing to RRD.[2] At a masterclass at the fifth World ROP Congress held in September 2022, experts agreed that to assess the risk for the development of RRD in PAR, it would be necessary to classify PAR based on the way it is expected to behave. Category-1 PAR would be secondary to regressed Type 2 ROP,[3] which is usually a small area in anterior zone 2 or zone 3. Because these eyes never had a vitreoretinopathy, this PAR is likely to be relatively innocuous, with risk as much as in other myopic eyes. Category-2 PAR would be from spontaneously regressed Type 1 ROP, which was advised treatment but was lost to follow-up without treatment, commonly encountered in developing countries. Category-3 PAR is secondary to treatment with anti-VEGF, and this category seems to be of main focus considering the increasing use of anti-VEGF as monotherapy. Experts believe PAR after anti-VEGF monotherapy is akin to man-made familial exudative vitreoretinopathy, and many practitioners perform laser photocoagulation of PAR in early life to prevent late reactivations and RRD.[4] In both categories 2/3, the development of a previous vitreoretinopathy is presumably believed to contribute to a higher chance of the formation of breaks and RRD. In the Indian scenario, we also encounter an undetermined category, where older children are found to have PAR, and give a history of prematurity without any old records of stage/severity of ROP. These eyes are best excluded from clinical trials, or separately classified, for future accurate risk assessment studies. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.