Zone I retinopathy of prematurity.

Two (5.4%) of 37 patients with retinopathy of prematurity were noted to have zone I vascularization of the retina in at least one eye. Three eyes in the two patients showed plus disease with nonflorid stage 3 ridge formation and extraretinal fibrovascular proliferation. Two of the three eyes were not treated and rapidly progressed to total retinal detachment and blindness. The third eye was treated with cryotherapy and this was followed by resolution of the plus disease. Although the treated eye did not develop dragging of the retinal vessels or retinal detachment, it is unfortunately blind.