title: The "double-layer sign": in vivo imaging of polypoidal choroidal vasculopathy.
abstract: OBJECTIVE
  Polypoidal choroidal vasculopathy (PCV), a disease of the choroidal vascular network, presents clinically with polyp-like reddish orange lesions, as well as retinal pigment epithelial (RPE) and/or neurosensory retinal detachments. Optical coherence tomography (OCT) is a useful diagnostic tool that provides cross-sectional and volumetric imaging of posterior segment microstructure. Typical OCT findings in PCV may reveal a classic hyperreflectivity in the choroidal layers known as the "double-layer" sign. This sign is indicative of an abnormal choroidal vascular network. Indocyanine green angiography is also useful for the diagnosis of PCV and clearly identifies the polyp-like lesions arising from the choroidal vasculature.
  
  
  METHODS
  A 53-year-old African American woman presented with complaints of gradually decreasing vision in the left eye (OS). Clinical examination revealed moderately reduced acuity OS with a small central scotoma found on Amsler grid testing. Dilated fundus examination revealed a hemorrhagic RPE detachment with suspicion of a choroidal neovascular membrane in the foveal region of the OS. Exudative leakage appeared circumferentially around the macula OS. Optical coherence tomography of the OS also revealed two highly reflective layers: one at the level of the RPE and another beneath the RPE ("double-layer" sign). The patient was referred to a retina subspecialist for angiography and treatment consideration.
  
  
  CONCLUSIONS
  It is important to distinguish PCV from other variants of choroidal neovascularization. The polyp-like lesions found in the PCV are a unique and classic characteristic. Proper diagnostic workup includes stereoscopic posterior fundus evaluation and imaging studies, including OCT and indocyanine green angiography.
authors.affiliation: *OD †OD, FAAO Nova Southeastern University, Fort Lauderdale, Florida.
authors.forename: Jamie M
authors.initials: JM
authors.lastname: St Martin
authors.forename: Julie
authors.initials: J
authors.lastname: Rodman
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Pizzimenti
authors.forename: Eva
authors.initials: E
authors.lastname: Duchnowski
mesh_terms: D002829:Choroid / Q000098:blood supply; D020256:Choroidal Neovascularization / Q000175:diagnosis*; D005260:Female; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D006801:Humans; D008875:Middle Aged; D011127:Polyps / Q000175:diagnosis*; D012163:Retinal Detachment / Q000175:diagnosis; D012607:Scotoma / Q000175:diagnosis; D041623:Tomography, Optical Coherence / Q000379:methods*; D014792:Visual Acuity