Stages 2 and 3
Stage 2 ROP: the ridge of mesenchymal tissue with greater width and height and extends above the plane of the retina (Figures 2C and 2D). Early on, the ridge may be white, evolving to pink or red as ROP progresses. Neovascular tufts rising from the retinal surface are termed “popcorn proliferation” and, though neovascularization, are not considered stage 3 findings unless connected to the ridge .
Stage 3 ROP: the ridge develops extraretinal fibrovascular proliferation (EFP) or neovascularization, which extends into the vitreous cavity (Figures 2E and 2F).
On occasion stage 2 or 3 ROP will regress and retinal vascularization will proceed past the ridge, only to recur. In such eyes, a second demarcation line (“double demarcation line”) may form. When a double demarcation line is present, the ROP is graded according to the most anterior pathology.