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

In reply  We appreciate the interest of Drs Topilow and Ackerman in our article.¹ Their clinical impression that a wider avascular zone indicated a greater probability of the ROP advancing rapidly to severe disease preceded the publication of the Multicenter Trial of Cryotherapy for ROP² (CRYOROP) data. However, the focus of our study is different. All of the patients included in the series described by Topilow and Ackerman^3-5 were treated with cryotherapy, some were treated after developing retinal detachment. Little data were presented on the patients' findings prior to the development of severe ROP,³ and no comparison was made between the size of the avascular zone in their patients and that of other premature infants who never developed threshold disease. We studied patients prior to retinal detachment or cryotherapy, and the emphasis of our report was on findings in early screening examinations that help predict an