Patterns of Choroidal Configuration in Pachychoroid Spectrum Disease.

Objective: To assess choroidal alterations across clinically defined pachychoroid entities using ultra-widefield OCT angiography (OCTA) and to compare them with controls without retinal disease. Design: Prospective observational study at a tertiary referral center. Participants: A total of 101 eyes from 69 participants were included (52 pachychoroid-related; 49 controls). The pachychoroid-related group comprised 27 eyes with chronic central serous chorioretinopathy (CSC), 15 eyes with pachychoroid neovasculopathy (PNV), and 10 eyes with aneurysmal type 1 choroidal neovascularization. Participants were matched for age and sex. Methods: Ultra-widefield swept-source OCTA was performed using a 24 × 20-mm scan protocol with field-based analysis on a predefined 3 × 3 grid. Main Outcome Measures: Ultra-widefield OCTA derived measures including choroidal thickness; choroidal flow density (CFD); absolute and area-normalized choroidal vascular and stromal volume; choroidal vascularity and stromal indices; and intervortex vein anastomosis, each assessed across predefined central and peripheral regions. Results: Eyes with chronic CSC showed globally increased choroidal thickness, accompanied by concurrent expansion of both vascular and stromal volumes across central and peripheral regions, together with globally reduced CFD. In PNV, choroidal thickness was preserved and no volumetric enlargement was detected; changes were spatially confined and characterized by regionally reduced CFD in peripheral regions. Aneurysmal type 1 choroidal neovascularization demonstrated neither choroidal thickening nor vascular or stromal volumetric enlargement but was characterized by relative stromal predominance in central and selected peripheral regions and by a near-global reduction in CFD. In pachychoroid spectrum eyes, intervortex vein anastomoses coursing through the central sector were associated with lower area-adjusted vascular and stromal volumes in peripheral regions, with no significant associations in controls. Conclusions: Distinct choroidal patterns suggest that pachychoroid entities are not defined by a uniform trajectory toward a thicker or more vascular choroid. The findings emphasize that single choroidal metrics do not reliably characterize pachychoroid entities. Two nonexclusive interpretations may underlie pachychoroid heterogeneity, including venous overload with adaptive drainage and neovascularization functioning as a hemodynamically relevant outlet that disrupts a previously closed choroidal vascular system. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.