ABSTRACT
AIM:To explore the influence factors of the treatment zone diameter(TZD)and its correlation with axial length growth(ALG)after Paragon CRT orthokeratology.METHODS: Retrospective clinical study. The data of 226 myopic patients(226 eyes)wearing Paragon CRT orthokeratology from April 2020 to September 2022 were collect. The correlated factors of TZD after wearing lens for 1mo, and the relationship between the overlapping treatment zone/ pupil area ratio and the ALG after wearing lens for 1a were analyzed.RESULTS: After wearing lens for 1mo, the TZD was negatively correlated with central corneal thickness(CCT)and positively correlated with the flat corneal eccentricity. After wearing lens for 1a, the ALG of the small TZD group(0.25±0.18mm)was significantly smaller than that of the large TZD group(0.34±0.24mm, P=0.002), and the ALG of the small area ratio group(0.24±0.19mm)was significantly smaller than that of the large area ratio group(0.35±0.23mm,P<0.001). Age and overlapping treatment zone area/pupil area ratio were significantly associated with the ALG in multivariate linear regression(all P<0.05).CONCLUSION: The wearers with thicker CCT and smaller flat corneal eccentricity usually had smaller TZD, and both the TZD and the overlapping treatment zone area/pupil area ratio were correlated with the ALG.
ABSTRACT
AIM: To construct and validate a diagnostic model for early detection of keratoconus based on parameters in Sirius.METHODS: The study comprised of 46 early keratoconus eyes(including 20 right eyes and 26 left eyes in 34 patients)and 46 age- and gender-matched normal eyes(including the right eyes of 46 patients)in the prediction group. The predictive index was constructed using LASSO and Logistic regression analyses based on the topographic, pachymetric and aberrometry variables of Sirius. There were 23 early keratoconus eyes categorized as suspected keratoconus cases by Sirius(including 12 right eyes and 11 left eyes in 23 patients)and 23 age- and gender-matched normal eyes(including the right eyes of 23 patients)included in the application cohort. External validation of predictors was performed for the application cohort.RESULTS: Sirius Keratoconus Index(SKI)was calculated based on the minimum corneal thickness and symmetry index back of Sirius. Highest AUC values were obtained in the prediction group(AUC=0.932)after Logistic regression analysis. The cut-off value of SKI was set at 0.44. Then, the receiver operating characteristic(ROC)curve, calibration plot and nomogram of the diagnostic formula were analyzed for the prediction cohort in detail. Finally, the accuracy of the SKI was evaluated in the application cohort; the sensitivity was 91% and the specificity was 96%.CONCLUSION: SKI based on minimum corneal thickness and symmetry index back of Sirius is a simple and effective method for early detection of keratoconus in the preoperative screening for refractive surgery.