Optical density ratio in the subretinal fluid: Differentiating chronic central serous chorioretinopathy and polypodial choroidal vasculopathy

Purpose To investigate the differences in the optical density ratios between chronic central serous chorioretinopathy (CSC) and polypoidal choroidal vasculopathy (PCV) obtained from subretinal fluid (SRF) analyses to identify the diagnostic role of optical density ratios. Design Retrospective cohort study. Methods Patients with acute CSC (n = 36), chronic CSC (n = 38), and PCV (n = 32) were included in the study. Spectral-domain optical coherence tomography (SD OCT) images of SRF were analyzed. The optical density measurements were obtained by using ImageJ. The optical density ratios were calculated from the SRF to the vitreous, retinal pigment epithelium (RPE), and retinal nerve fiber layer (RNFL) reflectivity ratios. Results Optical density ratios of SRF to the vitreous, RPE, and RNFL were significantly higher in patients with PCV than in those with chronic CSC (P =.002, P =.001, P =.001). There was no significant difference between acute and chronic CSC (P =.358, P =.433, P =.774). RPE reflectivity was significantly different between groups (P =.002) but no significant difference in vitreous and RNFL reflectivity were detected between groups (P =.172, P =.171). Conclusions The optical density ratio differs significantly between chronic CSC and PCV, but not between chronic and acute CSC. This suggests the usefulness of this parameter in differentiating between chronic CSC resembling PCV and PCV itself.