Research progress on the diagnostic techniques of early keratoconus / 国际眼科杂志(Guoji Yanke Zazhi)

@#Diagnosis of early keratoconus(KC)contributes to identifying potential patients before typical clinical symptoms. It also contributes to timely intervention of the progress of disease and improvement of long-term prognosis. Hence, it is crucial to prevent iatrogenic corneal ectasia and reduce the burden of keratoplasty. There are diverse kinds of early KC diagnosis techniques, including corneal topography, corneal aberrations, epithelial and corneal thickness measurement, corneal confocal microscopy, corneal biomechanics, and genetic examination. Since it is often difficult to ensure sufficient sensitivity and specificity with single technique, multiple techniques are beneficial to evaluate the cornea comprehensively, which may become the development tendency of early KC diagnosis in the future.

Predictive index based on minimum corneal thickness and symmetry index back of Sirius for early diagnosis of keratoconus / 国际眼科杂志(Guoji Yanke Zazhi)

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.

Comparison of the corneal volume and the anterior chamber volume using Pentacam in individuals with healthy, subclinical and early keratoconus eyes / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To compare the anterior chamber volume and corneal volume using Pentacam in people with early keratoconus, subclinical keratoconus, and healthy subjects.<p>METHODS: This epidemiologic study was performed on 63 patients who were candidates for refractive surgery. We classified our patients into three groups as normal, subclinical keratoconus, and early keratoconus according to the Amsler-Krumeich criteria. We collected demographic information, including age and sex, and obtained a full medical history of the patients. Complete visual examination was performed for all patients. Then, using Pentacam, corneal volume and anterior chamber volume were measured among three groups. <p>RESULTS: Corneal volume in the control group was significantly higher than the subclinical keratoconus and early keratoconus groups(<i>P</i><0.05), but the anterior chamber volume was not significantly different between the groups(<i>P</i>>0.05).<p>CONCLUSION: Measuring the corneal volume can help to distinguish the eyes with subclinical keratoconus and early keratoconus from normal eyes. The chamber volume might not differ remarkably among people with subclinical keratoconus, early keratoconus, and those with normal eyes.