Iris neovascularization and fibrovascular membrane

Introduction Iris neovascularization is not a primary disease of the iris, but is secondary to many eye diseases and certain systemic diseases. Because it can develop or merge with the formation of fibrous vascular membranes, so that the iris corneal angle is closed and severe neovascular glaucoma occurs, the intraocular pressure is often difficult to control, and eventually the eye is blinded and even the eyeball is removed due to severe eye pain. Therefore, it is very important to find and deal with it as soon as possible. After Bader described the iris neovascularization in 1868, many authors have reported iris neovascularization in patients with diabetes and central retinal vein occlusion. Due to advances in inspection techniques, particularly in the clinical application of fluorescein angiography, the discovery of iris neovascularization is increasing.

Cause

1. Vascular disease Central retinal vein occlusion, central artery occlusion, Eales disease, Coats disease, Leber microaneurysm, retinal hemangioma, choroidal hemangioma, retinopathy of prematurity and carotid artery obstructive disease.

2. Eye diseases endophthalmitis, sympathetic ophthalmia, Koyanagi-Harada disease (Vogt-Koyanagi-Harada disease), retinal detachment, secondary glaucoma, eye penetrating injury, etc.

3. Systemic diseases Diabetes, sickle cell disease, lupus erythematosus carotid artery obstructive disease, Marfan syndrome and Norrie disease.

4. Surgical and radiotherapy retinal detachment surgery, vitrectomy and cataract extraction, after radiation therapy.

5. Intraocular tumor retinoblastoma, iris melanoma, choroidal melanoma metastases and hemangiomas. Retinal ischemic diseases often occur in the iris, optic disc or retinal neovascularization, and can cause neovascular glaucoma or vitreous hemorrhage and blindness. Studies have shown that retinal ischemia is the main cause of iris neovascularization.

an examination

Related inspection

Iris examination ophthalmoscopy

The clinical course of iris neovascularization can be divided into three phases:

Phase 1: Early, neovascularization first appeared in the proximal pupil edge of the iris and in certain areas of the anterior chamber. Small curved and irregular red lines can be seen on the surface of the iris. The brown iris should be carefully examined to find the angle of the iris cornea. The width of the angle is still normal. The duration of this period varies with the cause of the disease. The central venous obstruction of the retina develops rapidly. The period lasts only for weeks or months; however, iris neovascularization in diabetic retinopathy often lasts for several years without progress.

Phase 2: The iris neovascularization continues to increase and fuse with each other until the entire surface of the iris is reticular, and there are more neovascularizations in the iris cornea, but there is no or only a few areas of the iris surrounding the anterior adhesion.

Phase 3: The surface of the iris is generally obscured by the neovascular membrane; due to the contraction of the fibrous vascular tissue, the pigmented layer is pulled forward to form the pupillary pigmentation valgus; the iris corneal angle is extensively surrounding the anterior adhesion, resulting in a sharp increase in intraocular pressure and neovascularization Glaucoma is significantly mixed and congested. Suffering from severe eye pain, vision only has a sense of light. In the iris neovascularization, the incidence of anterior chamber hemorrhage often reaches 25% or even higher. The amount of bleeding varies, but often it is difficult to absorb the disease. In addition to slit lamp examination, iris fluoroscopy can also be performed to detect the iris blood circulation by fluorescent angiography. Under normal circumstances, the iris vessels are regularly arranged in a radial pattern. The neovascularization on the surface of the iris is irregular or reticular, and fluorescein rapidly leaks from the neovascularization into the anterior chamber. There are also reports of iris indocyanine green angiography, but it is rarely used.

Differential diagnosis

Direct identification can be done without the need for differential diagnosis with other diseases.

The clinical course of iris neovascularization can be divided into three phases:

Phase 1: Early, neovascularization first appeared in the proximal pupil edge of the iris and in certain areas of the anterior chamber. Small curved and irregular red lines can be seen on the surface of the iris. The brown iris should be carefully examined to find the angle of the iris cornea. The width of the angle is still normal. The duration of this period varies with the cause of the disease. The central venous obstruction of the retina develops rapidly. The period lasts only for weeks or months; however, iris neovascularization in diabetic retinopathy often lasts for several years without progress.

Phase 2: The iris neovascularization continues to increase and fuse with each other until the entire surface of the iris is reticular, and there are more neovascularizations in the iris cornea, but there is no or only a few areas of the iris surrounding the anterior adhesion.

Phase 3: The surface of the iris is generally obscured by the neovascular membrane; due to the contraction of the fibrous vascular tissue, the pigmented layer is pulled forward to form the pupillary pigmentation valgus; the iris corneal angle is extensively surrounding the anterior adhesion, resulting in a sharp increase in intraocular pressure and neovascularization Glaucoma is significantly mixed and congested. Suffering from severe eye pain, vision only has a sense of light.

In the iris neovascularization, the incidence of anterior chamber hemorrhage often reaches 25% or even higher. The amount of bleeding varies, but often it is difficult to absorb the disease. In addition to slit lamp examination, iris fluoroscopy can also be performed to detect the iris blood circulation by fluorescent angiography. Under normal circumstances, the iris vessels are regularly arranged in a radial pattern. The neovascularization on the surface of the iris is irregular or reticular, and fluorescein rapidly leaks from the neovascularization into the anterior chamber. There are also reports of iris indocyanine green angiography, but it is rarely used.

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