Age-related macular degeneration (AMD) — wet (neovascular) type — is characterized by choroidal neovascularization (CNV). The MOST accurate imaging modality to precisely classify CNV as type 1 (sub-RPE), type 2 (sub-retinal), or type 3 (retinal angiomatous proliferation — RAP) is:
- A Fundus fluorescein angiography (FFA) alone
- B Spectral-domain OCT and OCTA with depth-resolved flow mapping ✓
- C Indocyanine green angiography (ICGA) alone
- D B-scan ultrasonography
Explanation
Spectral-domain OCT in combination with OCTA provides the best anatomical and flow-based localization of CNV relative to the RPE. Type 1 CNV (occult) lies beneath the RPE and appears as a hyporeflective space beneath the RPE on OCT; OCTA shows flow in the choriocapillaris-RPE plane. Type 2 CNV (classic) lies above the RPE in the subretinal space. Type 3/RAP involves intraretinal neovascularization anastomosing with the deep capillary plexus. FFA can identify classic vs. occult CNV but cannot depth-resolve the exact layer. ICGA is best for polypoidal choroidal vasculopathy and PCV. B-scan cannot resolve these layers.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.