In Diabetes, patients get leaky blood vessels and blockage of some circulation in the body, due to the effects of high blood glucose over time.
Leaky blood vessels cause fluid build up in the retinal tissues (oedema) leading to reduced vision. Treatment involves good control of the diabetes and blood pressure. Macular Laser treatment or repeated injections of antiVEGF or steroid may be given.
Blockage of the retinal circulation gives rise to lack of blood supply to the retinal tissues (ischaemia), triggering growth of fine new vessels on the retina (NVE) and iris (rubeosis). These fine new vessels bleed easily and cause vitreous haemorrhage with sudden loss of vision. They can also cause scar tissue formation and pull on the retina causing tractional retinal detachment.
New vessels should be treated urgently before bleeding occurs. Treatment involves laser to the retina to shut down the growth of these new vessels. Sometimes antiVEGF injections and vitrectomy surgery may be required to stop further growth.