The Clinical Application Of Anterior Segment OCT Measurement In The Diagnosis Of Dry Eye

Objective:Throuth imaging and measuring the lower tear meniscus parameters of subjects by Anterior segment OCT,to preliminary estimate the lower tear meniscus parameters of normal people of different age range,to evaluate the anterior segment OCT in the diagnosis of dry eye.Methods:Selection of outpatients in our hospital in 113 cases of dry eye patients(226 eyes),and 206 cases(410 eyes)of healthy volunteers were compared,using the fourth generation of Fourier-domain optical coherence tomography to image and measure the lower tear meniscus height(LTMH),lower tear meniscus area(LTMA),lower tear meniscus depth(LTMD)the central corneal epithelial thickness(CCET),central corneal thickness(CCT)of all of the subjects.The results of the two groups were compared and the Receiver operating curve(ROC)of the subjects was drawn to evaluate the application of the fourth generation anterior segment OCT in the diagnosis of dry eye.206 healthy subjects were divided into 4 groups by age,namely: 20<A group ≤30 years,a total of 108 eyes;30<B group ≤40 years,a total of 104 eyes;40<C group ≤50 years,a total of 102 eyes;50<D group≤60 years,a total of 96 eyes.Measurement of LTMH,LTMA,LTMD,CCET and CCT by the anterior segment OCT.The above results were compared with the results of the traditional dry eye diagnosis method and the reference value range of the lower tear meniscus parameters in different age groups was determined.Results:Through the U test of the data found that in dry eye group LTMH,LTMD,LTMA,CCET,and CCT was significantly lower than the control group,the difference was statistically significant(LTMH t=-24.932,P=0.000 LTMD;t=-9.633,P=0.000;LTMA t=-23.208 P=0.000;CCET t=-10.75 P=0.000;CCT,t=-5.86,P=0.000).Through the ROCcurve and calculate the area under the curve of the LTMH,LTMD,LTMA,CCET,CCT,cut-off values were: 269.83 um,122.02 um,0.0232mm2,54.16 um,531.50um;sensitivity were 85.4%,88.9%,96.5%,77%,66.8%;specificity: 91.7%,70.5%,75.1%,56.8%.59.8%.Spearman correlation analysis the lower tear meniscus parameters and dry eye diagnosis method,the results show that there were no correlation between central corneal thickness and other indicators,other indicators were negatively correlated with age,there were certain correlation between lower tear meniscus parameters and dry eye diagnosis indexes.The lower tear meniscus was positively correlated with NIBUTav parameters(LTMHr=0.397,LTMDr=0.402,P <0.05;LTMAr=0.409 P <0.05;CCETr=0.283,P,<0.05);The lower tear meniscus was positively correlated with Schirmer test(LTMHr=0.261,P<0.05,LTMDr=0.270,P<0.05;LTMAr= 0.272,P <0.05;CCETr=0.107,P <0.05)in addition,there were positive correlation and strong correlation between the each parameters of lower tear meniscus,(LTMH LTMAr=0.981,P <0.05;LTMH LTMDr=0.983,P <0.05;LTMALTMDr=0.990,P<0.05),the correlation coefficient is much higher than that of dry eye diagnosis index of correlation.The lower tear meniscus of4 age group was measured by Anterior segment OCT,their LTMH reference range respectively(A:355.72~440.74um;B:322.65~378.24um;C:274.52~ 331.70um;D:232.33~318.69um)LTMD reference range respectively(A:160.93~188.58um;B:138.93~166.09um;C:113.99~138.41um;D:85.21~ 115.05um)LTMA reference range respectively(A:0.031~0.038mm2;B:0.027~0.033mm2;C:0.023~0.028mm2;D:0.013~0.018mm2).Conclusion:Through the observation and measurement of OCT images showed that the lower tear meniscus image area of dry eye group were less than control group and the all measurements of dry eye group were reduced,the boundary lines are blurred and the coherence is poor,and the turbidity of tears is increased.LTMA,LTMH,LTMD can be used as a new target for the diagnosis of dry eye,of which LTMA and LTMH are more effective.In addition,there was a good correlation between the lower tear meniscus parameters measured by anterior segment OCT and the indexes of dry eye traditional diagnosis.The reference value range of the lower tear meniscus parameters decreased gradually with the increase of age.The anterior segment OCT is expected to become a clinical diagnosis of dry eye after the follow-up of new diagnostic tools.