The measurement of anterior chamber depth andaxial length with the IOLMaster compared withcontact ultrasonic axial scan

AIM: To compare the measurement of anterior chamber depth (ACD) and axial length (AL) by IOLMaster and contact ultrasonic (US) axial scan (A-scan).· METHODS: Measurements of ACD and AL were prospectively obtained in 137 eyes of 121 subjects with the IOLMaster compared with measurements with the US.· RESULTS: There was an excellent correlation between IOL Master and US measurements for the ACD (r =0.823;P < 0.001) and AL (r =0.996;P <0.001). The mean values of the parameters measured by IOLMaster and US were, respectively, as follows: ACD, 2.94±0.49mm, 2.58±0.51mm; AL, 24.37±3.04mm, 23.81±2.83mm. The mean differences of ACD and AL values between IOLMaster and US measurements were 0.36±0.30mm, 0.56±0.34 mm respectively, and they proved to be statistically significant (P < 0.001), with the 95% limits of agreement (LoA) from -0.08mm to +0.38mm for ACD and from -0.09mm to +0.69mm for AL.· CONCLUSION: As noncontact biometry, IOLMaster provides accurate values. A high degree of agreement between US and IOLMaster was noted. It not only has the advantage of performing noncontact examinations, but also produces various additional data simultaneously and may thus obviate the need for multiple examinations. Further studies are needed to assess the interchangeability of measurements in clinical practice.