Choroidal neovascularization

Choroidal neovascularization is the creation of new blood vessels in the choroid layer of the eye. This is a common symptom of the degenerative maculopathy wet AMD (age-related macular degeneration).

Causes
CNV can occur rapidly in individuals with defects in Bruch's membrane, the innermost layer of the choroid. It is also associated with excessive amounts of Vascular Endothelial Growth Factor (VEGF). As well as in wet AMD, CNV can also occur frequently with the rare genetic disease pseudoxanthoma elasticum and rarely with the more common optic disc drusen.

Symptoms
CNV can create a sudden deterioration of central vision, noticeable within a few weeks. Hemorrhaging of the new blood vessels can accelerate the onset of symptoms of CNV.

Treatment

 * In 'wet' (also known as 'neovascular') Age-Related Macular Degeneration, CNV is treated with photodynamic therapy coupled with a photosensitive drug such as verteporfin. The drug is injected into the eye, where it accumulates in the new blood vessels. It is then activated by a laser light. The drug destroys the new blood vessels, and prevents any new vessels forming by forming thrombi.


 * Anti-VEGF drugs, such as pegaptanib and ranibizumab, are also used to treat CNV. Anti-VEGFs bind to and inactivate Vascular Endothelial Growth Factor.