| Objective:Keratoconus is a progressive corneal dilated disease that is thought to be a multifactorial disorder caused by an interaction of genetic and environmental factors.This study aims to statistically analyze the morphological and mechanical parameters of corneal keratoconus patients and healthy examiners(no other eye diseases except refractive error),so as to provide a theoretical basis and basis for keratoconus screening and diagnosis in clinical work,and explore the risk factors related to the development of keratoconus.Methods:This retrospective case-control study included 44 patients diagnosed with keratoconus at Shenyang He Eye Hospital between November 2019 and November2021,and 44 healthy patients with sex-and age-matched patients with no eye disease other than refractive error.All patients were collected by the Ocular Surface Disease Index(OSDI)scale.Factors included were: family history,eye rubbing,smoking,allergies,hours of daylight,dry eyes and contact lens wear.Corneal morphology was assessed using the Pentacam 3D Oculus Optikgerate Gmb H,Wetzlar,Germany,which included parameters including Flat Keratometry(K1),steep Keratometry(K2),mean keratometry(km),and radius of curvature of the anterior and posterior surfaces Anterior Radius of Curvature(ARC),Posterior Radius of Curvature(PRC),Astig,Thinnest Corneal Thickness(TCT),Apical Corneal Thickness(ACT),Central Corneal Thickness(CCT),Anterior Chamber Depth(ACD).Corvin biomechanical parameters were measured using a visual corneal biomechanical analyzer(Corvis ST,Oculus,Germany),including Corvis Biomechanical Index(CBI),Belin/Ambrosio Deviation Value(BADD),Tomographic and Biomechanical Index(TBI),Adjusted AP1-b IOP(SP-A1),Ambrosio’s Relational Thickness(ARTh),Integrated Radius Index(IR)and the Deformation Amplitude Ratio(DA-R).SPSS25.0 statistical software was used for data analysis and processing,independent sample t-test and nonparametric test were used to compare the differences in corneal topographic parameters and biomechanical parameters between keratoconus group and control group,and the predicted values of CBI,BAD-D,TBI,SP-A1 and ARTh in keratoconus patients were determined by receiver operating characteristics(ROC)curve analysis and optimal cut-off value.The risk factors of keratoconus were identified through univariate and multivariate logistic regression analysis.Results:The keratoconus group included 44 patients(84 eyes)with an average age of 25.15±1.33 years,and the control group consisted of 44 healthy subjects(no eye diseases other than refractive errors)(88 eyes)with an average age of 23.15±0.68 years.There were no significant differences in age or sex between the two groups(P>0.05).The anterior surface K1 of keratoconus group was significantly higher than that of the control group 45.30(42.50,49.20)vs.43.00(41.57,44.32),P<0.001;the anterior surface K2 of keratoconus group was significantly higher than that of the control group 49.00(44.80,51.9)vs.44.3(42.47,45.22),P<0.001,and the anterior surface Km of keratoconus group was significantly higher than that of the control group 46.7(44.1,49.6)vs.43.75(42.07,44.82),P <0.001;the anterior surface astigmatism of keratoconus group was significantly higher than that of the control group 2.4(1.7,3.8)vs.0.9(0.6,1.5),P<0.001;the posterior surface K1 of keratoconus group was significantly higher than that of the control group-6.5(-7.3,-6.1)vs.-6.2(-6.3,-6.0),P<0.001;the posterior surface K2 of keratoconus was significantly higher than that of the control group-7.1(-8.1,-6.6)vs.-6.6(-6.8,-6.4),P <0.001;The posterior surface of keratoconus was significantly higher than that of the control group-6.8(-7.6,-6.3)vs.-6.4(-6.5,-6.2),P< 0.001.The posterior surface astigmatism of keratoconus group was significantly higher than that of 0.5(0.4,0.8)vs.0.4(0.3,0.5),P<0.001 in the control group,the anterior surface radius of keratoconus group was significantly lower than that of the control group 7.22(6.8,7.61)vs.7.74(7.54,8.03),P<0.001,and the posterior surface radius of keratoconus group was significantly lower than that of the control group5.67(4.94,6.1)vs.6.38(6.19,6.64),P <0.001;TCT,CCT and ACT in keratoconus group were significantly lower than those in the control group,P<0.001,and the best corrected visual acuity(BCVA)in the keratoconus group was significantly lower than that in the control group by 0.42 vs.0.00,P <0.001,the OSDI score of keratoconus group was significantly higher than that of the control group 22.91(8.85,31.25)vs.10.88(2.60,20.62),P<0.05,and intraocular pressure in keratoconus group was significantly lower than that in the control group 12(11,14)vs.16(14.75,18),P<0.001.According to the ROC curve analysis,the areas under the BAD-D,TBI,CBI,SP-A1 and ARTh curves of keratoconus patients were 0.927,0.94,0.877,0.85 and 0.84,respectively.BAD-D predicts an optimal cut-off of keratoconus of >0.84,with a sensitivity of 86% and specificity of 98%.TBI predicts an optimal truncation of keratoconus of >0.82,a sensitivity of 84%,and a specificity of 98%.CBI predicts an optimal truncation of keratoconus of > 0.69,with a sensitivity of 73% and specificity of 95%.SP-A1 predicts an optimal cut-off of keratoconus of <0.60,with a sensitivity of 73% and specificity of87%.ARTh predicts an optimal cut-off of keratoconus of <0.65,with a sensitivity of68% and specificity of 98%.Taking keratoconus as the dependent variable and risk factors as independent variables,logistic stepwise regression analysis showed that patients with eye rubbing and dry eye syndrome were significant risk factors for keratoconus,while there were no significant differences in family history,smoking,allergic reactions,and sunshine time.In multivariate analysis,eye rubbing(OR: 7.29,95% CI: 1.34-39.61,P=0.021)and dry eye(OR: 5.89,95% CI: 1.01-34.16,P=0.048)were possible risk factors for disease development.Conclusion:The results showed that there were obvious differences in corneal morphological parameters and mechanical parameters between keratoconus patients and healthy patients with physical examination(no other eye diseases except refractive error).At the same time,CBI,TBI,BAD-D,SP-A1 and ARTh can well predict the occurrence of keratoconus,among which BAD-D has the highest sensitivity and specificity.In addition,eye rubbing and dry eye may be risk factors for keratoconus. |
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