What Is Choroidal Neovascularization?

Choroidal neovascularization refers to proliferating blood vessels from choroidal capillaries, which expand through the rift of Bruch membrane, between Bruch membrane and retinal pigment epithelium, or between neuroretina and retinal pigment epithelium, or between retinal pigment epithelium and choroid Proliferation, many diseases involving the RPE-Bruch membrane-choroidal capillary complex can lead to the formation of CNV, also known as subretinal neovascularization. It is more common in the macula, which damages central vision. This disease has become one of the main causes of blindness. It is common in adult eyes, especially those over 60 years of age. It should be detected early and dealt with in a timely manner.

Basic Information

Visiting department: Ophthalmology
Multiple groups: Adults over 60 years
Common locations: Choroid

Common causes: Degenerative diseases, hereditary macular degeneration, inflammatory diseases, tumors, injuries and other factors
Common symptoms: No early symptoms, loss of vision, deformed vision, dark spots at the center or side, permanent vision impairment, etc.

Etiology of choroidal neovascularization

Many disease processes can affect retinal pigment epithelium-Bruch membrane-choroidal capillaries, and are often accompanied by subretinal neovascularization. According to their nature, these diseases can be divided into the following categories:

Degenerative disease

Age-related macular degeneration, degenerative myopia, optic disc warts, and blood vessel-like streaks of the fundus.

2. Hereditary macular degeneration

Best disease, Stargardt disease, yellow-spotted retinal degeneration, hereditary primary glass warts, and adult-type macular pigment atrophy.

3. Inflammatory diseases

Ocular tissue cytoplasmosis syndrome, toxoplasmosis, clauroid choroiditis, rubella retinopathy, sarcoidosis, acute posterior pole multiple squamous pigment epithelial lesions, central exudative choroidal lesions Rieger type), Harada disease and Behcet disease.

4. Tumor

Choroid pigment nevus, choroid osteoma, choroid hemangioma, choroid melanoma, choroidal metastatic cancer, retina and pigment epithelial hamartoma, etc.

5. damage

Late complications after choroidal rupture, argon laser treatment, or retinal condensation injury.

6. Idiopathic

unknown reason.

Clinical manifestations of choroidal neovascularization

Early in the appearance of new blood vessels under the retina, without symptoms. As it gradually expands, leaks, and ruptures, it can cause vision loss, deformed vision, and dark spots at the center or sides. Symptoms recur, the macula is severely damaged, causing permanent vision impairment. During general fundus examination, it appears as exudation and bleeding. A more reliable indication is the presence of subretinal hemorrhage. Because the bleeding is located on the deep side of the pigment epithelium, it is dark red, cyan gray, or brown gray, and the border is clear. If the hemorrhage penetrates the pigment epithelium and reaches the retina, it will appear bright red under the neuroepithelium or in the neuroepithelium. A small amount of bleeding can penetrate the retinal neuroepithelium and escape into the vitreous. Another sign is the appearance of lipidoid exudation. Retinal neuroepithelial detachment can be seen in the neovascular area, which is different from retinal neuroepithelial detachment in central serous choroidal retinopathy. Cystic macular edema may occur in patients with a longer course. Choroidal neovascularization persists for months or years and gradually stabilizes. It is replaced by a gray-yellow fibrous vascular membrane, which can turn white afterwards, and finally form a retinal choroidal atrophy area.

Choroidal neovascularization

Experimental inspection

Laboratory tests can be performed for primary diseases.

2. Auxiliary inspection

(1) Fundus fluorescence angiography is the most valuable method for detecting choroidal neovascularization. The early phase of choroidal angiography is the choroid phase, which can identify the shape of choroidal neovascularization, showing a lace-like or single-wheel shape, or fan-shaped expansion to the periphery. Intravenous fluorescein leaks out from the wall of the new blood vessel, forming a localized strong fluorescent region. Late fluorescein slowly diffuses from the edge of the neovascular membrane into the retinal neuroepithelial detachment zone.

(2) Indocyanine green angiography (ICGA) has obvious advantages in choroidal neovascular membrane imaging. Choroidal neovascularization blocked by blood, turbid fluid, or occult neovascularization on FFA can often be found in ICGA.

3. When optical coherence tomography (OCT) is used for choroidal neovascularization, it can visually display changes in the tissue structure and neovascularization of the retina, providing a new inspection method for further research.

Choroidal neovascularization

The diagnosis can be determined based on clinical manifestations and typical fundus fluorescein angiography and morphology. Indocyanine green angiography can improve the detection rate.

Choroidal neovascularization

Drug treatment

There are currently no treatment-specific drugs. Indomethacin drugs have a certain effect on inhibiting the growth of new blood vessels under the retina. According to various causes of inflammation, rational use of antibiotics and corticosteroids can reduce or subside the inflammatory response. Various vitamins can support retinal metabolism.

2. Photocoagulation therapy

Photocoagulation is an effective method for treating new blood vessels under the retina, which is to close the new blood vessels. Adapted to active subretinal neovascularization outside the fovea. Two weeks after photocoagulation, the affected eye was examined by fluorescent angiography for serous or hemorrhagic detachment and leakage. If there is a residual leak or recurrence of new blood vessels, repeat photocoagulation. If the symptoms recur, or if the presence of fluid in the diseased area is confirmed by slit lamp contact lens examination, repeat fundus fluorescein angiography, indocyanine green angiography, and OCT should be repeated, and treatment should be performed when indicated.

3. Photodynamic therapy (PDT)

Single and repeated PDT treatments can partially or completely block choroidal neovascularization in elderly macular degeneration (AMD). Multiple PDT treatments can block CNV and reduce the risk of vision loss caused by AMD. PDT treatment does not affect the normal retinal and choroidal tissues around the lesion, and has no damage to vision.

4. Surgery

In vitreous surgery, on the basis of technical operations such as retinal membrane anterior and posterior membrane dissection and retinal incision, patients who were suitable for surgical treatment successfully underwent subretinal neovascular membrane resection and achieved positive results. In addition, macular transposition is also successfully used in the treatment of subchoroidal neovascular membranes.

5. Other

Transpupillary diathermy (TTT), photon, and proton radiation are also effective.