iris neovascularization
Introduction
Introduction to iris neovascularization Iris neovascularization is not a primary disease of the iris, but is secondary to many eye diseases and certain systemic diseases. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of infection: non-infectious Complications: anterior chamber hemorrhage, neovascular glaucoma
Cause
Iris neovascular cause
(1) Causes of the disease
Clinical studies have shown that about 40 kinds of ocular or systemic diseases can occur in iris neovascularization, which are summarized as follows:
1. Vascular diseases: 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. Surgery and radiation therapy: retinal detachment surgery, vitrectomy and cataract extraction, after radiation therapy.
5. Intraocular tumors: retinoblastoma, iris melanoma, choroidal melanoma, metastatic carcinoma and hemangioma.
Retinal ischemic diseases often occur in the iris, optic disc or retinal neovascularization, and can cause neovascular glaucoma or vitreous hemorrhage, resulting in blindness of the eye. Studies have shown that retinal ischemia is the main cause of iris neovascularization.
(two) pathogenesis
In the past 50 years, the most popular theory of ocular neovascularization suggests that hypoxia is a major factor in stimulating neovascularization and a response to hypoxia. Ashton et al. and Wise have suggested that retinal veins or capillaries can be blocked. Stimulates neovascularization, which causes circulatory disorders and cellular ischemia or hypoxia. Cells that are hypoxic but not necrotic can produce angiogenic factors that induce neovascularization. Human, bovine and rabbit retinal extracts have:
1 The ability to stimulate cell proliferation in bovine vascular endothelial cell culture;
2 stimulating the ability of chicken embryo yolk sac membrane neovascularization, experimental monkey eye as central retinal vein occlusion, followed by iris neovascularization or neovascular glaucoma, vascular proliferative activity in aqueous humor, vitreous or intraocular fluid, however Normal aqueous humor, vitreous or intraocular fluids do not have this activity. Recent studies have shown that in retinal ischemic diseases such as diabetic retinopathy and retinal vein occlusion, intraocular vascular endothelial growth factor levels are significantly increased, resulting in iris regeneration. Angiogenesis.
Latikaien et al observed 48 patients with central retinal vein occlusion and found that the iris vessels in the non-ischemic group were normal and no neovascular glaucoma occurred. In the ischemic group, neovascular glaucoma with iris redness was more common. In addition, the iris itself Chronic hypoxia, inflammation, tumor and vascular primary factors can cause iris neovascularization.
Clinical observation and modern laboratory basic research found that neovascularization and capillary basement membrane dissolution, endothelial cell chemotaxis and migration, mitosis, neurite outgrowth, development, etc., a series of processes and a variety of vascular growth factors and blood vessels Growth factors are out of control disorders.
Prevention
Iris neovascularization
Early detection and treatment of primary diseases that may cause neovascularization of the iris.
Complication
Iris neovascular complications Complications, anterior chamber hemorrhage, neovascular glaucoma
Anterior chamber hemorrhage and neovascular glaucoma.
Symptom
Iris neovascular symptoms common symptoms eye congestion iris neovascularization and...
The clinical course of iris neovascularization can be divided into three phases:
No. 1: Early, the new blood vessels first appeared in the near pupil edge of the iris and in some areas of the angle of the eye. The curved surface of the iris was seen with small curved and irregular red lines. The brown iris should be carefully examined to find the iris corneal angle. The width of the angle of the anterior chamber is still normal. The duration of this period varies with the cause of the disease. The central venous obstruction of the retina develops rapidly. This period only lasts for several weeks or several months. However, the iris neovascularization of diabetic retinopathy often maintains the number. Year 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, markedly mixed and congested, suffering from severe eye pain, only light perception in the eyesight, anterior chamber hemorrhage often occurs in the iris neovascularization, the incidence rate can reach 25% or even higher, the amount of bleeding varies, but often the course of disease It is difficult to absorb, and in addition to the slit lamp examination, iris fluoroscopy can also be performed. Fluorescence angiography can clearly show the iris blood circulation in the light iris. Under normal circumstances, the iris blood vessels are radially arranged regularly, and the iris surface is reborn. The blood vessels are irregularly linear or reticulated, 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. According to the slit lamp examination and the FFA examination results, the diagnosis can be confirmed. .
Examine
Iris neovascularization
On the pathological section of the eyeball, the capillaries attached to the surface of the atrophic iris are visible. The wall is extremely thin, from the iris root to the surface of the iris corneal reticular tissue. On the other side, the fibrous connective tissue is connected to the pupillary margin, and the pupil is pulled. The pigmented epithelium in the posterior and iris layers is the cause of uveal pigment eversion in the pupil margin.
The FFA examination can clearly show the iris blood circulation. The neovascular surface on the iris surface is irregularly linear or reticulated, which can be accompanied by different degrees of fluorescein leakage. The obvious neovascularization on the iris surface can be found by slit lamp examination. .
Diagnosis
Iris neovascular diagnosis
Through clinical manifestations, the examination can be diagnosed.
