Small abnormal blood vessels called telangectasia (also known as arteriovenous (AV) malformations) can occur on the back of the eye (retina). Retinal telangiectasia can cause leakage of fluid out of the blood vessels onto the back of the eye (exudates) or bleeding, which can affect vision. Patients with Revesz syndrome or Coats plus are particularly liable to this complication. Regular monitoring is advised, as laser treatment of abnormal vessels can prevent these problems. VEGF injections, danazol or oestrogens may also be of benefit.