retinopathy signs and symptomsprolific retinopathyprolific pl2302pre proliferative diabetic retinopathyproliferative vitreous retinopathyhypertensive retinopathy symptomsproliferative vitreo retinopathybackground retinopathy symptomsautoimmune retinopathy symptomscentral serous retinopathy symptomsearly background diabetic retinopathynon proliferative