The iris neovascularization is the abnormal growth of blood vessels on the iris or on the anterior structures of the eye. There is no normal for these ocular parts to have visible blood vessels.
These abnormal blood vessels are created in order to supply oxygen to the eye in cases when the retina is deprived of oxygen or is ischemic, like in diabetic retinopathy or in retinal vein occlusion.
A very common condition secondary to the iris neovascularization is called neovascular glaucoma. This happens because the formation of these abnormal blood vessels obstructs the outflow of the aqueous humor from the anterior part of the eye, causing an increase of the intraocular pressure.