Repeatability of automatic measurements by a new spectral domain optical coherence biometer and agreement with a validated biometer

Purpose: To evaluate the repeatability of measurements obtained with a new spectral-domain optical coherence tomography-based biometer (Colombo IOL II, Moptim) and assess their agreement with those provided by the IOLMaster 700 (Zeiss). Setting: I.R.C.C.S. Bietti Foundation, Rome, Italy. Design: Prospective evaluation of diagnostic test. Methods: Patients underwent 3 consecutive scans with the Colombo IOL II and 1 with the IOLMaster 700. Two groups were analyzed: Group A included a series of consecutive patients undergoing phacoemulsification and Group B a series of subjects with a clear lens. Axial length (AL), keratometry, keratometric astigmatism, anterior chamber depth (ACD), lens thickness (LT), corneal diameter (CD), central corneal thickness (CCT) and retinal thickness (RT) were analyzed. The within-subject standard deviation (Sw), intrasession test variability, coefficient of variation (CoV) and intraclass correlation coefficient (ICC) were calculated for repeatability analysis. 95% limits of agreement were calculated to assess agreement with the IOLMaster 700. Results: Ninety-six unoperated eyes of 96 patients were enrolled (Group A: 45 Group B: 51). The CoV was low for most parameters, as it ranged between 0.04% (AL) to 4.47% (RT) in Group A and from 0.03% (AL) to 2.23% (LT) in Group B. Keratometric astigmatism measurements were less repeatable. Good agreement with the IOLMaster 700 was found for K, LT and AL, whereas the mean ACD was higher by 0.07±0.11 mm with the Colombo IOL II (p <0.0001). Conclusion: Measurements by the Colombo IOL II showed high repeatability and good agreement with those provided by the IOLMaster 700.