PURPOSE. During refractive error studies in children, we often measure the axial length of the eye. Ultrasound biometry provides the "gold standard" axial length measurement, but it requires cycloplegia and corneal anesthesia. The purpose of our study is to compare the non-cycloplegic and cycloplegic axial length measurements, using the IOLMaster, to cycloplegic ultrasound biometry. METHOD. Twenty-three children (ages 10-14) participated in the study. Measurements using the IOLMaster were performed until five measurements with a signal-to-noise ratio of 5 or greater were recorded prior to cycloplegia. Five measurements were also taken after cycloplegia (2 drops of 1% tropicamide) using the Humphrey Ultrasonic Biometer Model 820 (Humphrey Instruments, San Leandro, CA). The average of the five values was calculated for each technique, and the 95% limits of agreement were calculated to compare the IOLMaster data to the ultrasound data.
RESULTS. The mean axial lengths measured by non-cycloplegic IOLMaster were on average (±SD) 0.06 ± 0.19 mm longer than ultrasound (p=0.14), and the mean cycloplegic IOLMaster was 0.05 ± 0.18 mm longer than ultrasound (p=0.21), but neither was significantly different. The 95% limits of agreement ranged from -0.30 to +0.43 mm for the non-cycloplegic IOLMaster and -0.31 to +0.41 mm for the cycloplegic IOLMaster data.
CONCLUSIONS. Non-cycloplegic and cycloplegic measures of axial length using the IOLMaster agree with the "gold standard" cycloplegic ultrasound biometry in children, but the IOLMaster does not require the use of cycloplegic agents or topical anesthetic.