Measurement of Anterior Chamber Depth and Axial Length with IOL-Master or Contact Ultrasonic Axial Scan: Comparison and Correlation

  Objective  To compare the results of the IOL-Master and contact ultrasonic axial scan (US Ascan) for anterior chamber depth (ACD) and axial length (AL) measurements.

  Methods  A total of 161 eyes of 92 cases were enrolled in this study. ACD and AL estimation were measured with IOL-Master and contact US A-scan, and the corneal curvature was measured by IOL-Master and computer refractometery.

  Results  The ACD measured by IOL-Master and contact US A-scan was (2.94±0.19) mm and (2.77±0.13) mm, respectively, which showed significant difference (P < 0.001); however, these two methods showed no significant correlation (r=0.012, P>0.05). The AL measured by IOL-Master and contact US A-scan was (24.10±2.36) mm and (23.91±2.13) mm, which was significantly different between these two measurement methods (P < 0.01), and the two measurement methods showed significant correlation (r=0.983, P < 0.001). The corneal curvature measured by IOL-Master and computer refractor keratometer was (44.38±1.66) D and (44.12±1.62) D, respectively, which showed significant difference (P < 0.001).

  Conclusions  Both IOL-Master and contact US A-scan can be used for the measurement of anterior segment parameters. Based on optical prin-ciples, IOL-Master can reliably measure ACD and AL, and thus provides a new option for clinical biological measurements.