Comparison of anterior chamber depth measurements using three methods and the influence factors in age-related cataract patients / 国际眼科杂志(Guoji Yanke Zazhi)

ABSTRACT

@#AIM: To compare the measurement results of anterior chamber depth(ACD)by Pentacam, IOL Master and Contact Ultrasonic A-scan, and analyze the difference, correlation, consistency and influencing factors of the three measurement methods.<p>METHODS: In this study of 307 eyes of 250 cataract patients with preoperative, ACD estimation was done by Pentacam, IOL Master and Contact Ultrasonic A-scan. The independent sample <i>t</i>-test, Analysis of Variance(ANOVA), Pearson's correlation test and multiple linear regressions were used to analyze the results.<p>RESULTS: The mean of ACD measured by Pentacam(ACDp), IOL Master(ACDi)and A-scan(ACDa)were 2.42±0.45mm, 2.96±0.43mm, 2.58±0.36mm, the difference was statistically significant(<i>F</i>=136.694, <i>P</i><0.05). The three methods were sequentially compared in pairs, and the differences within the groups were statistically significant(<i>P</i><0.05). Pearson's correlation test was performed on the three methods in pairs, and there was a linear positive correlation within each group. When the ACDp and the central corneal thickness(CCT)were added, the sum(ACDp2)was no statistically significant compared with the ACDi(<i>P</i>=0.93). When the ACDp was less than 1.85mm(ACDi was about 2.40mm), the ACDa increases significantly and the fluctuation increases. Among the many possible influencing factors, axial length, lens thickness and age have the highest relative importance for ACD measurement.ACD was positively correlated with axial length(<i>r</i>Pentacam=0.602, <i>r</i>IOL Master=0.603, <i>r</i>A-scan=0.483), and negatively correlated with the lens thickness(<i>r</i>Pentacam= -0.382, <i>r</i>IOL Master= -0.350, <i>r</i>A-scan= -0.582), negatively correlated with age(<i>r</i>Pentacam= -0.328, <i>r</i>IOL Master= -0.414, <i>r</i>A-scan= -0.265). Three factors were included in the multiple linear regression model, and the age factor of Contact Ultrasonic A-scan was eliminated due to the low influence weight.<p>CONCLUSION: ACDp2 and ACDi may be closer to the true value of the anterior chamber depth. The Contact Ultrasonic A-scan may increase the measurement error when measuring shallow anterior chamber. Axial length, lens thickness and age have the greatest influence on ACD measurement, which are the influencing factors of Pentacam and IOL Master, but age is not the influencing factor of Contact Ultrasonic A-scan.