ABSTRACT
@#AIM: To compare the differences and agreement in axial length(AL), anterior chamber depth(ACD)flat axial corneal curvature(K1)and steep axial corneal curvature(K2)measured by SW-9000 and IOL Master 500.<p>METHODS: Totally 258 eyes of 129 patients with ametropia were measured with SW-9000 and IOL Master 500. Among them, 159 eyes were low to moderate myopia(-0.75D≤ spherical equivalent <-6D)and 99 eyes were high myopia(spherical equivalent ≥-6D). Comparison between two devices were performed for AL, ACD, K1, and K2. The difference between two instruments were evaluated with a paired samples <i>t</i>-test. The correlation between the measurements was evaluated using Pearson correlation coefficients. The agreement between the devices was evaluated with Bland-Altman plots. <p>RESULTS: There was significant difference between SW-9000 and IOL Master 500 in measuring AL and ACD(all <i>P</i><0.01), but there was no significant difference between K1 and K2 in patients with low to moderate myopia. There was no significant difference in AL, ACD and K1 between SW-9000 and IOL Master 500(all <i>P</i>>0.05), but there was significant difference in K2(<i>P</i><0.05)in patients with high myopia. Pearson correlation analysis showed that AL, ACD, K1 and K2 of patients with low to moderate and high myopia were highly correlated(all <i>P</i><0.01). Bland-Altman consistency analysis showed that the two methods had good consistency in measuring AL in patients with low to moderate and high myopia, but poor consistency in measuring ACD, K1 and K2.<p>CONCLUSION: SW-9000 and IOL Master 500 have good consistency in measuring the AL of people with ametropia. The measurement of ACD and corneal curvature has poor consistency, and should be carefully selected in combination with clinical practice.
ABSTRACT
Objective To evaluate the repeatability and agreement of two optical biometers (Lenstar LS900 (R) and SW-9000) for ocular biometry in Chinese adolescents.Methods A prospective study was conducted which included 65 ametropic patients,with an average age of (11.45 ± 2.67) years (age ranging from 8 to 18 years).The ocular biometry for right eyeball was performed with Lenstar LS900 (R) and SW-9000 respectively,followed by evaluation of the repeatability of the two biometers using one-way analysis of variance,and the agreement of the two instruments using the Bland-Altman plot.Results The repeatability of parameters measured by Lenstar LS900 (R),including axial length (AL),K value in the flattest meridian (K1),K value in the steepest meridian (K2),central corneal thickness (CCT),anterior depth (AD),lens thickness (LT),pupil diameter (PD),was well,and all intraclass correlation coefficient (ICC) ＞ 0.9;the repeatability of white to white (WTW) was inferior to other parameters,but it was still ＞0.88.The repeatability of AL,K1,K2,CCT measured by SW-9000 was good,with their ICC ＞ 0.9,but the repeatability of other parameters was poor.The parameters with good repeatability including AL,K1,K2,CCT measured by SW-9000 and Lenstar LS900 (R) were compared respectively,and the results showed that AL and CCT examined by SW-9000 were slightly longer than those measured by Lenstar LS900 (R),and the difference was statistically significant (all P ＜ 0.05).However,there was no significant difference about K1,K2 (all P＞0.05).Moreover,the AL,K1,K2 and CCT measured by the two instruments had close linear correlation (all r ＞0.97,all P ＜0.01).The BlandAltman plot showed that 95％ LoA (limits of agreement) of AL was (-0.057 to 0.133) mm,K1 was (-0.456 to 0.369) D,K2 was (-0.388 to 0.549) D and CCT was (-3.483 to 8.016) μm.Conclusion Biometric parameters including AL,K1,K2,CCT measured by Lenstar LS900 (R) and SW-9000 have good repeatability in the adolescents aged 8-18 years and they are highly correlated;meanwhile,the agreement of AL,K1,K2,CCT measured by SW-9000 with Lenstar LS900 (R) is acceptable in clinical practices.