Angiogenesis within the eye can lead to visual abnormalities and impaired vision. Although new vessels may arise anywhere in the retina, they are most commonly seen at the posterior pole. Neovascularization near the disc carries a worse prognosis than neovascularization elsewhere.
Vascular Endothelial Growth Factor (VEGF) causes neovascularization and is upregulated due to hypoxia.
The disease progression is slow and remains asymptomatic for an extended period. By the time the patient experiences visual impairment, the disease will have likely progressed significantly.
Vitreous hemorrhage is defined as the extravasation of blood into one of the several potential spaces formed within and around the vitreous body. This is a notable finding in PDR.
Eventual fibrosis of vitreal vessels will pull on the retina, predisposing these patients to retinal detachment. Patients will often report that "a curtain fell" over their vision, and must be treated urgently.
Glaucoma is a disease that causes progressive optic atrophy. It is usually due to increased intraocular pressure (IOP). In this subset of patients, neovascularization can impair the outflow of aqueous humour, leading to increased IOP and glaucoma.
Findings characteristic of non-proliferative diabetic retinopathy (NPDR) like soft exudates, hard exudates, hemorrhages and a macular star may be present.
Laser photocoagulation causes the newly formed vessels to regress by inducing ischemia. Panretinal photocoagulation is achieved using a Nd:YAG laser (neodymium-doped yttrium aluminum garnet).
Surgical procedure depends on the severity of the patient's condition. Options include iridotomy, vitrectomy, and retinal repair, among others.
Bevacizumab is an anti-VEGF drug. It is given via intravitreal injection and slows angiogenesis.
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