This multicenter, retrospective observational cohort study was conducted as a part of the Macula Society International CSCR Research Network (MICRoN) and adhered to the tenets of the Declaration of Helsinki. Institutional Review Board (IRB) approval was obtained from all participating centers, with a waiver of informed consent granted due to the minimal-risk and retrospective nature of the study. Data sharing agreements among collaborators and the procedures for demographic, clinical, and imaging data collection and analysis have been detailed in prior publications of the project. All images were meticulously analyzed by an experienced retina specialist (NH) and 10% of the sample images were independently reviewed and validated by another masked grader (AZ) to ensure accuracy and consistency. In case of disagreements, the measurements and segmentations were adjudicated by the senior author (JC).

Of the entire dataset provided by collaborators, patients with active acute CSCR (presence of SRF) who resolved at follow-up (complete absence of fluid) following a single episode of CSCR without active intervention or medications known to treat CSCR were included. Exclusion criteria included: Patients with recurrent, persistent or chronic CSCR, patients with imaging signs of chronic or sequelae of chronic CSCR like choroidal neovascularization (CNV) confirmed on fluorescein angiography and/or OCT angiography, RPE atrophy or cystoid macular edema, and those who underwent treatment including photodynamic therapy (PDT), focal laser photocoagulation, and subthreshold laser, as well as medications including anti-vascular endothelial growth factor injections, mineralocorticoid antagonists, or carbonic anhydrase inhibitor medication. Patients with other diseases affecting visual acuity (significant cataract, pathological myopia etc.) were also excluded from the study. Collected data included age at baseline, sex, systemic comorbidities, and systemic steroid use. Best-recorded Snellen visual acuity (BRVA) at baseline and follow-up was converted to logMAR (LogMAR). The duration of symptoms before presentation was measured in weeks and duration between baseline and final visit was measured in months. Patients were divided into 2 groups based on BRVA at final follow-up following resolution of SRF. Better outcome group included patients who had visual acuity equal to or better than 20/20 (could read all letters or miss no more than 2 letters on the 20/20 line) and worse outcome patients with visual acuity of 20/25 or worse. BRVA was recorded as visual acuity with current spectacles, followed by pinhole visual acuity as confirmed by all collaborators. Patients with a maximum symptom duration of up to 24 weeks prior to presentation and a minimum follow-up of at least 3 months from baseline were included in the study.

An experienced grader (NH) evaluated multimodal imaging data including autofluorescence (AF), fluorescein angiography (FA), optical coherence tomography (OCT), and OCT angiography, as available for each patient. RPE alteration area was measured in disc diameters using AF when available or other modalities, including infrared imaging (IR) or FA when AF was not available. Based on RPE changes observed in AF, IR, or FA images, CSCR was classified as either simple CSCR in which a single area of RPE alteration not exceeding 2 disc areas was present, or complex CSCR, which included RPE alteration more than 2 disc areas or multifocal RPE alterations. When FA was available, the type of leak and presence of subfoveal leak (within the central 1 mm of the fovea) were recorded. Volumetric OCT scans with clear visualization of the choroidoscleral junction were analyzed for OCT-based measurements. Central macular thickness (CMT), subfoveal choroidal thickness (SFCT), SRF height, subfoveal Haller’s layer thickness (HLT), and inner choroidal thickness (ICT) were measured according to previously explained methods in a prior publication from the group. Central retinal thickness (CRT) measured from the ILM to the outer border of photoreceptor outer segments (PROS) above the SRF. At baseline, PROS morphology was described as either uniformly elongated, irregularly elongated or speckled in appearance. Following resolution, ellipsoid zone band was classified as continuous, discontinuous or atrophic. Change in retinal thickness was measured as CMT at follow-up minus the CRT at baseline as we wanted to evaluate the retinal thickness without considering the subretinal fluid. Similarly change in SFCT was measured as difference between follow up and baseline SFCT. Inter-class coefficient was calculated between the masked graders (NH and AZ) for thickness measurements including CMT, SFCT, HLT, and lesions (SRF height, PED height) of randomly selected 10% of the OCT volumes from the cohort.

Statistical analysis was performed using SPSS statistical software version 23 (SPSS Inc., Chicago, IL, USA). Categorical variables were expressed by frequency and percentage and continuous ones by mean (SD; SD) or median (IQR; IQR) depending on the normality of distribution as assessed by the Shapiro-Wilk test. Chi-square tests were used to analyze categorical variables among groups. Paired t-test and Wilcoxon signed-rank test were used to cf baseline and follow up data with and without normal distribution, respectively. Independent Student t-test and Mann Whitney test was used to cf baseline and follow up parameters between the 2 groups according to the distribution of data. Parameters that were significant on univariate logistic regression were considered for multivariate logistic regression. Baseline logMAR was multiplied by 10 to express the odds ratio per 0.1-unit change in visual acuity (equivalent to one Snellen line), improving interpretability and numerical stability. A P -value of less than 0.05 was considered statistically significant.