OCT of the macula in a 72-year-old woman with dry AMD shows intraretinal fluid, subretinal fluid, and a sub-retinal pigment epithelium (sub-RPE) lesion with double-layer sign. Fluorescein angiography demonstrates early hyperfluorescence with late leakage in the subfoveal region. The lesion is best classified as:
- A Occult CNV (sub-RPE neovascularization) — type 1 CNV ✓
- B Classic choroidal neovascularization (CNV) — type 1
- C Type 2 CNV (sub-retinal classic membrane)
- D Type 3 CNV (retinal angiomatous proliferation — RAP)
Explanation
Type 1 CNV (occult, sub-RPE) grows under the RPE and on FFA shows early stippled hyperfluorescence with late pooling (fibrovascular PED pattern). The OCT double-layer sign — RPE lifted off Bruch's membrane by a fibrovascular complex — is characteristic. Type 2 CNV (classic) breaks through the RPE into the subretinal space and appears as early bright hyperfluorescence with distinct lacy borders and late leakage on FFA. RAP (type 3) is an intraretinal neovascular complex with dilated retinal vessels anastomosing with choroidal vessels; it shows hot-spot fluorescence. Despite being 'occult', type 1 CNV in neovascular AMD responds well to anti-VEGF.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.