Comparison of IOL Master and contact ultrasound A-scan in the measurement of axial length of cataract

Abstract

Objective To compare the measurement of axial length (AL) for routine cataract eyes by Optical coherence biometry (IOL Master) and contact ultrasonic axial scan (CUSAS).Methods Measurements of AL were prospectively obtained in 300 eyes of 286 subjects with the IOL Master compared with that from the CUSAS.Results The mean values of AL measured by IOL Master and CUSAS were(20.58±0.43) mm and (20.51±0.52) mm in the hyperopia group (AL≤ 22mm),(23.85±0.75) mm and (23.81±0.73) mm in the normal group (22 mm＜AL≤26mm),(28.27± 1.11) mm and (28.25±1.00) mm in the high myopia group A (AL＞26 mm without posterior scleral staphyloma),(29.44±2.28) mm and (29.19±2.20) mm in the high myopia group B (AL＞26mm with posterior scleral staphyloma).There was a statistically significant difference between IOL Master and CUSAS measurements for AL in the high myopia group B (t=3.93,P=0.00) while there was no statically significant difference in other groups (P＞0.05).Conclusions As a non-contact biometry,IOL Master provides accurate values.A high degree of agreement between IOL Master and CUSAS is noted.Further studies are needed to assess the interchangeability of measurements. Key words: Axial length; IOL Master; Contact ultrasonic axial scan