How does neovascular glaucoma occur?

Neovascular glaucoma occurs in the face of ischemic retina, usually from diabetes or a past central retinal artery occlusion. The hungry, blood starved retinal tissue pumps out VEGF molecules in order to create new blood vessels. These blood vessels, however, are poorly controlled and tend to cause problems such as bleeding in the back of the eye.

The VEGF can percolate forward through the pupil into the front part of the eye and cause new blood vessels to grow on the iris. This is called NVI or “neovascularization of the iris.” If if these vessels grow into the trabecular meshwork (NVA or neovascularization of the angle), they can close off aqueous outflow and cause a serious acute glaucoma.

Neovascular glaucoma is difficult to treat. You try to decrease production of aqueous with betablockers and CAIs, perform PRP laser of the retina if you can see it, but often these patients require some sort of glaucoma surgery (usually a tube placement).

To get a better idea what iris neovascularization looks like, you might want to watch this video of NVI at TimRoot.com