Fig. 2.

Gass classification system of retinal angiomatous proliferation. Stage 1. Atrophy of the outer retina (arrow) with approximation of retinal capillaries and occult Type 1 subretinal pigment epithelium choroidal new vessels. Stage 2. Anastomosis (arrow) of retinal capillaries with Type 1 new vessels. Stage 3. Proliferation of Type 2 new vessels in the subretinal space (arrow). SSRN, subsensory retinal choroidal neovascularization. Stage 4. Activation of Type 1 vessels causing serous retinal pigment epithelium (RPE) detachment (arrows). Stage 5. Compound piggyback Type 2-Type 1 cicatricial disciform lesion with overt CRA (arrow).⁷