Comparison Of The Consistency And Influencing Factors Of Children’s Intraocular Pressure Measurements Results Obtained By Icare Rebound Tonometry And Noncontact Tonometry

Objectives:To investigate the consistency of Icare rebound tonometry（RBT）and non-contact tonometry（NCT）in children’s intraocular pressure measurement.To investigate the effects of central cornea thickness（CCT）,axis length（AL）,anterior chamber depth（ACD）,corneal curvature on the two intraocular pressure tonometry.Methods:632 eyes of 316 children who were treated in our ophthalmology clinic between May 2021 and December 2021 were selected.Each participant was measured intraocular pressure using RBT and NCT,AL-Scan Measure CCT,AL,ACD,corneal curvature.Based on the NCT measurements,the eye examination was divided into 3 groups.Group A:10～15mm Hg,group B:16～21mm Hg,group C:>21mm Hg.Wilcoxon paired rank test,Spearman correlation analysis and Bland-Altman consistency analysis were used to analyze the differences,correlations and consistencies between NCT and RBT measurements in the whole,group A,group B and group C,respectively.According to the CCT,it is divided into group I（CCT<520μm）,group II（520μm≤CCT≤570μm）,groupⅢ（CCT>570μm）,The consistency and correlation between NCT and RBT measurements were analyzed within the group and as a whole,respectively.Multiple linear regression analysis was performed using intraocular pressure as the dependent variable and age,CCT,AL,ACD,and corneal curvature as the independent variables.Results:The NCT measurement range of all examined eyes was 10 to29mm Hg,with an average of 17.37±3.16mm Hg,and the RBT measurement range was 10.7 to 25.0mm Hg,with an average of 17.05±2.36mm Hg,the difference in measured values between the two is statistically significant（P=0.001）.The measurement results of RBT in group A was higher than that of NCT,while the opposite was true in group B and group C,the difference between the two tonometer in the three groups was statistically significant（P<0.05）,and the mean difference increased with the increase of intraocular pressure,and the difference was the largest in group C.Spearman rank correlation analysis showed a significant positive correlation between NCT and RBT measurements r=0.825（P<0.05）.Bland-Altman consistency analysis showed that the average difference between NCT and RBT measurements was 0.3mm Hg overall,95%Lo A is-3.2～3.8mm Hg,within the bounded range,the absolute value of the maximum difference between the two is 3.8mm Hg.In group A,B and C,the average difference between NCT and RBT measurements was-1.0mm Hg,0.6mm Hg and2.7mm Hg,respectively.95%Lo A was-3.4～1.4mm Hg,-2.3～3.6mm Hg,-0.7～6.1mm Hg,respectively;Within the bounding range,the absolute values of the maximum difference between the two are 3.4mm Hg,3.6mm Hg,and 6mm Hg,respectively.CCT measurements with an average of 557.62±32.17μm,Spearman correlation analysis showed that both NCT and RBT intraocular pressure measurements were positively correlated with CCT(IOP_NCT/CCT:r=0.481,P=0.000,IOP_RBT/CCT:r=0.415,P=0.000).The linear regression equations are:IOP_NCT=-8.742+0.047×CCT,IOP_RBT=0.648+0.029×CCT.The difference in measurements between the two methods is statistically significant in groups I and III（P<0.05）,The difference in II group was not statistically significant（P>0.05）.The analysis found that with the increase of CCT values,the measurement values of the two tonometry also increased,and the increase in RBT was smaller than that of NCT.After multiple linear regression analysis,the results showed that the RBT measurements were not significantly correlated with CCT（P<0.0001）and ACD（P=0.014）,and were not significantly correlated with age（P=0.164）,AL（P=0.214）and corneal curvature（P=0.086）.The NCT measurements were correlated with CCT（P<0.0001）,ACD（P=0.015）,AL（P=0.046）,and corneal curvature（P=0.046）,where corneal curvature was inversely correlated with NCT and not significantly correlated with age（P=0.798）.Conclusions:1.In the intraocular pressure measurement of children,the RBT and NCT measurement results have a good correlation and consistency within the normal intraocular pressure range.When intraocular pressure>21mm Hg,the measurement value of intraocular pressure is very different,and it is necessary to consider comprehensively to avoid missed diagnosis or misdiagnosis.2.When intraocular pressure in children was measured using RBT,the measurements correlated with CCT and ACD,regardless of age,AL,or corneal curvature.When measured with NCT,it is associated with CCT,ACD,AL,corneal curvature,and is not related to age.