Photoreceptor outer segment layer thinning as a biomarker in acute central serous chorioretinopathy.

Background: The photoreceptor outer segment (PROS) layer demonstrates focal thinning above the fluorescein leakage in acute central serous chorioretinopathy (CSC); however, the nature of this phenomenon is not known.

Objectives: To study the relationship between the PROS layer and thickness of the outer retinal layers above the fluorescein leakage in newly diagnosed acute CSC.

Design: Single-center retrospective study.

Methods: All participants received multimodal imaging, including fluorescein angiography and optical coherence tomography. Thickness of PROS, outer nuclear layer (ONL), and ONL-outer plexiform layer (OPL) complex was measured above the leakage and outside the leakage within the area of neurosensory detachment. The number of intraretinal hyperreflective foci of the outer retina was counted. The correlation between PROS thickness and ONL, OPL-ONL complex thickness, and the number of intraretinal hyperreflective foci was calculated.

Results: Fifty eyes of 48 patients (38 males and 10 females, 43.8 ± 10.6 years) with a mean symptom duration of 1.4 ± 1.3 months were included. PROS thickness above the fluorescein leakage showed a statistically significant correlation with ONL thickness, OPL-ONL complex thickness, and the number of hyperreflective foci in the outer retina, 0.57, 0.60, and -0.46, respectively (p < 0.001). Measuring the extent of PROS thinning above the leakage in newly diagnosed CSC allowed to predict self-resolution of subretinal fluid. The greatest linear dimension of PROS thinning showed an area under the receiver operating curve (ROC) curve of 0.98. The cases without PROS thinning had the fastest resolution of subretinal fluid.

Conclusion: PROS thinning above the fluorescein leakage in acute CSC is associated with thinning of the outer retinal layers and reveals mild outer retinal atrophy. The absence of PROS thinning predicts faster resolution of CSC.