​ANZNN records the worst stage: None-yes examined, no changes seen; Stage I - Demarcation line separating avascular from vascular retinal regions; Stage II - Ridge - demarcation line increased in volume to extend out of the plane of the retina; Stage III - Ridge with extra retinal fibrovascular proliferation. May be continuous with posterior edge of ridge or posterior but disconnected from the ridge, or into the vitreous; Stage IV - Retinal detachment. In Stage IV the detachment is subtotal, and for Stage V there is total detachement; Not examined - No eye examination performed.