Abstract: Objective To investigate the features of the retina outer layers on images of spectral domain optical coherence tomography (SD-OCT) in acute central serous chorioretinopathy (CSC). Design Retrospective case series. Participants 55 eyes of 55 patients who were diagnosed as unilateral and initial onset of acute CSC with one obvious leakage point (LP) on fundus fluorescence angiography (FFA) images. Methods The morphology of RPE reflective layer at LP, macular fovea (MF) and neurosensory retinal detachment (NSRD) were investigated, and the morphology features of NSRD were also analyzed on SD-OCT with Spectralis HRA+OCT. Main Outcome Measures The subtypes of PED, the morphologic and structural changes of the retina outer layers on the SD-OCT. Results 41 eyes(74.5%) of LP displayed as PED, among which 15 eyes (27.3%) presented as dome-shaped PED (DSPED) and 26 eyes (47.2%) flat irregular PED (FIPED) . FIPED was prone to display as inkblot leakage (χ2=11.116，P=0.001) and locate outside of foveal avascular zone (FAZ) (χ2=4.432，P=0.035) compored with DSPED. 6 eyes (10.9%) in MF and 9 eyes (16.4%) in NSRD presented as FIPED. 55 eyes (100%) manifested thickening hyper-reflectivity of outer plexiform layer (OPL) and 53 eyes (96.4%) demonstrated with fusiform or multiple irregular hypo-reflective regions within OPL, which seemed as splitting of OPL. The external limiting membrane (ELM) of 55 eyes (100%) was intact and distinct. The outer segments of photoreceptors layer (PRL-OS) of 44 eyes (80.0%) were thickening and with vague ellipsoid zone (EZ) and interdigitation zone (IZ). The boundary of PRL-OS in 44 eyes (80.0%) showed granular appearance and in 41 eyes (74.5%) accompanied with hyperreflective dots (HRD). Conclusion FIPED in acute CSC is not rare, and the thickening of PRL-OS, granular appearance of PRL-OS and indistinction of EZ and IZ are frequently-occurring signs. The appearance of splitting-shaped hypo-reflecitive regions within thickening OPL of NSRD is a common and important sign in acute CSC. (Ophthalmol CHN, 2022, 31: 200-204)

Key words: acute central serous chorioretinopathy, spectral domain optical coherence tomography, pigment epithelium detachment, splitting of outer plexiform layer