Inner Collagenous Layer Detachment: A Novel Optical Coherence Tomography Sign in Avascular Serous Pigment Epithelial Detachment Secondary to Central Serous Chorioretinopathy

This case series describes a novel optical coherence tomography (OCT) finding in avascular serous pigment epithelial detachment (PED) secondary to central serous chorioretinopathy (CSC), and evaluates its multimodal imaging features and clinical relevance. Two patients with CSC demonstrated a well-demarcated, hyperreflective band extending between the retinal pigment epithelium and Bruch's membrane within the serous PED on macular OCT. Multimodal imaging, encompassing fluorescein angiography and OCT angiography, was employed to ascertain the absence of neovascularization, thereby substantiating the avascular nature of the lesion. The structure exhibited dynamic behavior, characterized by a regression with PED resolution and subsequent reappearance with recurrence. This OCT finding, termed inner collagenous layer detachment (ICLD), is indicative of a localized separation within Bruch's membrane. ICLD may serve as a novel imaging biomarker of PED activity in CSC, thereby offering insights into its underlying pathophysiology. Further studies are needed to determine its prevalence, specificity, and potential role in clinical management.