Choroidal neovascularisation

An abnormal growth of blood vessels in the choroid layer of the eye

Choroidal neovascularisation (CNV) is a pathological condition characterized by the growth of new blood vessels originating from the choroid, a vascular layer of the eye, into the retina. This process is often associated with severe vision loss and is a hallmark of several ocular diseases, most notably age-related macular degeneration (AMD).

Pathophysiology

The choroid is a layer of blood vessels and connective tissue between the sclera and the retina. In CNV, new blood vessels break through the Bruch's membrane and invade the subretinal space. These vessels are often fragile and prone to leakage, leading to subretinal hemorrhage and fluid accumulation. This can result in retinal detachment and scarring, ultimately causing vision impairment.

Causes

CNV is most commonly associated with:

• Age-related macular degeneration (AMD)
• Pathologic myopia
• Ocular histoplasmosis syndrome
• Angioid streaks
• Choroidal rupture

Symptoms

Patients with CNV may experience:

• Distorted vision (metamorphopsia)
• Reduced central vision
• Dark or empty areas in the central vision (scotomas)
• Sudden onset of visual changes

Diagnosis

Diagnosis of CNV typically involves:

• Optical coherence tomography (OCT) to visualize the retina and choroid
• Fluorescein angiography to assess blood flow and identify leaking vessels
• Indocyanine green angiography for deeper choroidal imaging

Treatment

Treatment options for CNV include:

• Anti-VEGF therapy: Intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents such as ranibizumab, bevacizumab, and aflibercept
• Photodynamic therapy (PDT) with verteporfin
• Laser photocoagulation for certain types of CNV

Prognosis

The prognosis for CNV varies depending on the underlying cause and the timeliness of treatment. Early detection and treatment with anti-VEGF agents have significantly improved outcomes, reducing the risk of severe vision loss.

Also see

• Age-related macular degeneration
• Retinal detachment
• Optical coherence tomography
• Fluorescein angiography