Association of Retinal Pigment Epithelium Pump Function Reversal with Choroidal Vascularity Index in Treatment-Naïve
Patricia T A Bui1,2, Stefan Kickinger1,2, Daniel Ahmed-Balestra1,2
1Karl Landsteiner Institute for Retinal Research and Imaging, Vienna, Austria.
Objective:
To investigate the relationship between reversal of retinal pigment epithelium (RPE) pump function and choroidal architecture in treatment-naïve central serous chorioretinopathy (CSC), using choroidal vascularity index (CVI) as a quantitative biomarker.
Design:
Post hoc analysis of a prospective single-center cohort study.
Subjects:
Ninety eyes from 74 patients with treatment-naïve CSC were initially evaluated. Five eyes were excluded because of insufficient image quality, leaving 85 eyes from 70 patients for the final analysis.
Methods:
Eyes with treatment-naïve CSC underwent multimodal imaging. Swept-source OCT images were analyzed to assess choroidal architecture, including luminal area (LA), stromal area (SA), total choroidal area (TCA), and choroidal vascularity index (CVI), using a validated binarization technique. Reversal of RPE pump function was defined by either the presence of an intense inkblot leak on fluorescein angiography (FA) or a hyporeflective subretinal lucency sign on OCT. Associations between choroidal parameters and RPE pump reversal were evaluated using linear mixed-effects models to account for inter-eye correlation.
Main Outcome Measures:
Differences in CVI, TCA, LA, and SA in eyes with and without evidence of RPE pump reversal.
Results:
Retinal pigment epithelium pump reversal was observed in 58 eyes (68.20%). All exhibited an FA-based intense inkblot leak, and 8 eyes (13.79%) demonstrated the OCT-based hyporeflective subretinal lucency sign. Eyes with pump reversal showed significantly higher CVI (P = 0.005) and a nonsignificant trend toward greater LA (P = 0.083) than eyes without pump reversal. Total choroidal area and SA did not differ significantly between groups.
Conclusions:
Retinal pigment epithelium pump reversal is associated with increased CVI, suggesting a relationship between increased vascular proportion within the choroid and RPE dysfunction. In this context, CVI may serve as a useful marker of functional disease activity. These findings support the concept of CSC as a pachychoroid-driven disorder and provide further insight into its complex and multifactorial pathophysiology.
Financial Disclosures:
Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
