Early Retinal Vessel Development and Iris Vessel Dilatation as Factors in Retinopathy of Prematurity

In their article in the February 1996 issue of theArchives, Kivlin et al 1 conclude that, "... the risk of developing threshold ROP [retinopathy of prematurity] is inversely proportional to the maturity of the retinal vessels on early screening examinations." The eyes at risk that they describe have extensive peripheral zones of avascular retina that elaborate the vasoproliferative factors, which in turn cause preretinal neovascularization and subsequent traction retinal detachment. The smaller the area of vascularized retina, the larger the area of avascular retina. Their observation is not new. In our 1985 article, 2 we emphasized, In our clinical experience, the single most important prognostic factor determining the potential severity of ROP is the width and extent of the retinal avascular zone. The wider the zone, the greater the probability of rapid progression from early to advanced grades of disease. Our subsequent studies 3,4 reiterated this observation. Despite the fact that