PDR or proliferative diabetic retinopathy is one of the most serious complications of diabetic retinopathy occurring in about 5% of diabetics. PDR occurs when new blood vessels grow from the normal blood vessels on the retina or optic nerve. The growth of these vessels also results in the formation of a fibrous membrane. Contraction of this membrane pulls the gel away from the retina and can cause a bleed into the vitreous cavity resulting in a sudden onset of floaters and reduction in vision. The severity of vision loss is dependent on the extent of the bleed. A further complication of PDR is a retinal detachment. The detachment occurs when contraction of the fibrous membrane pulls the retina away from its normal position. Treatment of the new vessels, without other complications, is usually performed with a laser to shrink the abnormal vessels and prevent further leakage. More serious complications, such as vitreous haemorrhage and retinal detachment will require surgery. In this case, a vitrectomy may need to be performed in order to clear the bleed and therefore improve vision.