Changes in Stromal and Luminal Areas of the Choroid in Pachychoroid Diseases: Insights Into the Pathophysiology of Pachychoroid Diseases

PURPOSE. To evaluate and compare changes in choroidal vascular and stromal areas in patients with three major pachychoroid diseases for better insight into the pathophysiology of hese diseases. METHODS. Eighty-six eyes of 86 patients (50 men and 36 women; mean age, 49.1 years) were evaluated, including 21 patients with chronic central serous chorioretinopathy (CSC), 14 with pachychoroid pigment epitheliopathy (PPE), 19 with pachychoroid neovasculopathy (PNV), 14 with myopic choroidal neovascularization (mCNV), and 18 controls. Multimodal retinal imaging, including enhanced-depth imaging optical coherence tomography (EDI-OCT), was performed. Each EDI-OCT image was binarized with Image) software, and luminal (dark pixels) and stromal (light pixels) areas were calculated (3000 pm wide in the subfoveal choroid centered on the fovea). RESULTS. The subfoveal choroidal thickness (SFCT) was greater the three pachychoroid groups than in the control group (430.01 vs. 282.61 P < 0.001). There was no significant difference in SFCT among the three pachychoroid groups. The luminal-to-total choroidal ratio (L/C) was highest (ANOVA, P = 0.001) and the stromal-to-total choroidal ratio (S/C) lowest in the CSC group (ANOVA, I' = 0.001). Interestingly, stromal area changes were not correlated with SFCT in the CSC and PNV groups, in contrast to the good correlation between luminal area changes and SFCT in these groups. CONCLUSIONS. The eyes of CSC patients had significantly smaller choroidal stromal areas than those of controls or of PPE, PNV, or mCNV patients. The differences in choroidal stromal area, L/C, and S/C in different pachychoroid diseases may reflect different predominant pathogenic processes.