Neovascularization of the iris is not a primary disease of the iris, but is secondary to many eye diseases and certain systemic diseases. Because it can develop into or be combined with the formation of fibrovascular membranes, resulting in the closure of the iris angle and the development of severe neovascular glaucoma, intraocular pressure is often difficult to control, eventually leading to blindness in the affected eye or even the removal of the eye due to severe pain. Here’s how to diagnose iris neovascularization and fibrovascular membrane. Neovascularization first appears in the iris near the pupillary margin and in certain areas of the atrial angle. Tiny curved and irregular red lines are visible on the iris surface in the brown iris requiring careful examination to detect the iris angle examination to see that the atrial angle is still normal in width The duration of this period varies with the cause of onset, and those with central retinal vein obstruction develop rapidly and this period lasts only a few weeks or months; however, iris neovascularization occurring in diabetic retinopathy can often be maintained for several years without progression. The iris neovascularization continues to increase and fuse with each other until the entire iris surface becomes reticulated with neovascularization, and the iris corneal angle also has more neovascularization, but there are no or only a few areas of peripheral anterior iris adhesions. The iris surface is generally obscured by the neovascular membrane; the pupillary margin is ectopia due to contraction of the fibrovascular tissue, which pulls the pigment layer forward; and the iris angle has extensive peripheral anterior adhesions, resulting in a sharp increase in intraocular pressure and significant mixed congestion in neovascular glaucoma. The affected eye has severe pain, and vision is only light perception. In the case of iris neovascularization, the affected eye often has anterior chamber hemorrhage, which can occur at a rate of 25% or more. The amount of hemorrhage varies, but is often prolonged and difficult to absorb. In addition to slit lamp examination, fluorescence angiography of the iris can be performed to clearly show the iris blood circulation in light colored irises. Under normal conditions, the iris vessels are regularly arranged in a radial pattern. In contrast, the neovascularization of the iris surface is irregularly linear or reticulated and fluorescein rapidly leaks in large amounts from the neovascularization into the anterior chamber.