Methods
This study was designed to be a retrospective, observational and cross-sectional case series. A retrospective chart review was conducted for patients who were diagnosed with acute CSC from July 2011 to December 2014 at Kaohsiung Veterans General Hospital. The institutional review board and ethics committee of Kaohsiung Veterans General Hospital approved this study, which adhered to the tenets of the Declaration of Helsinki.
Idiopathic CSC was diagnosed based on the presence of a serous detachment of the neurosensory retina involving the macula that was confirmed using one of the following: SD-OCT, leakage at the RPE level using FA or choroidal hyperpermeability with ICGA. ICGA was not routinely performed but was used in cases where severe pachychoroid pigment epitheliopathy was suspected. None of them showed findings compatible with definitive PCV. Acute CSC was defined as the onset of subjective symptoms such as blurred vision, metamorphopsia, chromatopsia or micropsia that had occurred within the past 6 weeks. Recorded data included age, sex, disease onset duration, vision, biomicroscopic examinations, OCT images, fundus pictures and FA or ICGA if eligible. All OCT images were obtained through a dilated pupil using SD-OCT (Optovue, RTVue-CAM, Optovue, Fremont, California, USA or Heidelberg Spectralis OCT, Heidelberg Engineering, Heidelberg, Germany). These images were further classified using six parameters: foveal serous RD, PED, fibrinous exudates in the subretinal space, RPE bumps, thickened outer retina layer and hyper-reflective dots in the intraretinal and/or subretinal layer. Schematic representations are shown in figures 1, 2. Patients whose CSC development had strong association with steroid were excluded. These patients often have underlying diseases that could not tolerate discontinuation of systemic steroid treatment. Inclusion of such cases would complicate the evaluation as to whether it was the course of the disease or the effect of systemic steroid that contributed to the conditions observed. Eyes with other retinal abnormalities such as neovascular maculopathy (ie, polypoidal choroidal vasculopathy, age-related macular degeneration, idiopathic choroidal neovascularisation or retinal vascular diseases), intraocular inflammation and a posterior segmental tumour, and patients who were not followed-up for at least 3 months or had incomplete data were excluded. Observation and lifestyle modification were first recommended. Additional interventions were considered under the following rationales: CSC with persistent or increased macular subretinal fluid for 3 months or longer during follow-up or progressively decreased visual acuity. These patients were given further interventions, which included intravitreal injection of antivascular endothelial growth factor, photodynamic therapy or laser.
Figure 1Schematic diagrams of the six optical coherence tomography parameters. Arrow: hyper-reflective dots. Asterisk: thickened outer retina. Triangular arrowhead: fibrin. Arrowhead: pigment epithelial detachment. Note that the intraretinal bright dots are mostly observed in the outer layer of the neurosensory retina.
Figure 2Schematic diagram of the six optical coherence tomography parameters. Arrow: hyper-reflective dots. Asterisk: pigment epithelial detachment. Arrowhead: retinal pigment epithelial bumps.
Statistical analysis
Statistical analysis was performed using SPSS for Windows (V.20.0 software package; SPSS, Chicago, Illinois, USA). Differences in age, gender and SD-OCT characteristics between the observational group and treatment-needed group were compared using independent t-test and χ2 test. Multiple logistic regression analyses with forward selection were performed to determine significant prediction variables. Each patient was coded on the basis of presence of OCT characteristics, age and gender, to which each of the six OCT characteristics, aged ≥50 years and female, were scored an equal weight of 1 point. For the presence of each of the OCT characteristics, 1 point was coded and summed up. Idiopathic CSC is generally self-limiting and is more common in men between 20 and 45 years of age4 5; hence, it was hypothesised that older female might warrant more intense monitoring. Therefore, aged ≥50 years and female were each scored 1 point. The six OCT characteristics, as well as sex and age, were added stepwise as test variables in different receiver operating characteristic (ROC) analyses, and four model test variables A–D were thus developed. Model A represents the sum of the six OCT characteristics. Model B represents model A plus ‘hyper-reflective dots in the intraretinal layer and/or subretinal layer’. ‘Hyper-reflective dots in the intraretinal layer and/or subretinal layer’ was specifically selected because it was the only significant variable among the six OCT characteristics in χ2 test and multiple logistic regression test with forward selection. Model C represents model B plus sex, and model D represents model C plus age. Youden index was used as an index for the optimal cut-off of test variables. Finally, the corresponding sensitivity and specificity were calculated. Area under the ROC curve was employed to assess the discriminatory ability for intervention using a differential diagnosis strategy according to SD-OCT findings. A p value of <0.05 was considered to be statistically significant.
