SD-OCT of CNV SD-OCT is noninvasive and is the most practical visualization technique for the diagnosis and classification of CNV as well as for monitoring the response to treatment. SD-OCT reveals the elevation of the RPE and PEDs produced by type 1 CNV. Serous PEDs appear as sharply elevated, dome-shaped lesions with hollow internal reflectivity and typically no associated subretinal or intraretinal fluid. Fibrovascular PEDs may or may not be sharply elevated and typically demonstrate lacy or polyp-like hyperreflective lesions on the undersurface of the RPE, with or without signs of contraction (Fig 4-9; Activity 4-1). Chronic fibrovascular PEDs often have a multilayered appearance due to sub-RPE cholesterol crystal precipitation in an aqueous environment; this appearance has been termed the “onion” sign. The fibrotic “bridge arch–shaped” serous PED can develop following anti–vascular endothelial growth factor (anti-VEGF) treatment and is associated with poor visual outcome.