Diabetic retinopathy is classified as either non-proliferative diabetic retinopathy (NPDR) or proliferative diabetic retinopathy (PDR). NPDR, is an early stage where tiny blood vessels in the retina leak blood or fluid. Vision is still good at this stage. However, vision is affected when there is leakage involving the macula (macula oedema). PDR is present when abnormal vessels grow on the surface of the retina. This is due to insufficient blood flow to the retina, as a result of significant damage to retinal blood vessels. This new growth can cause scar tissue development or retinal detachment, which can lead to vision loss.