Assessment of measurement variability across automated biometry devices.

Purpose: To evaluate measurement variability between different readily available automated biometric devices for the purposes of improving surgeon decision making for phakic intraocular lens (IOL) sizing.

Setting: Private practice (Houston, TX, USA).

Design: Prospective, single center, bilateral, non-randomized, open-label, observational study.

Methods: This study included healthy eyes, with no prior eye surgery, and with a spherical equivalent of at least -1.00D. Orbscan II was compared to Argos, Atlas 9000, caliper, IOLMaster 500, IOLMaster 700, iTrace, Lenstar LS900, Pentacam HR, and Pentacam AXL Wave. Preoperative measurements included white to white (WTW), anterior chamber depth (ACD), and central corneal thickness (CCT). Linear mixed effect models were created to determine adjustment factor between the Orbscan II and other devices for WTW, ACD, and CCT measurements.

Results: A total of 204 subjects (408 eyes) completed the study. All mean WTW measurements were significantly different compared to the Orbscan II (p < 0.01), except for Pentacam AXL Wave. All mean ACD and CCT measurements were significantly different compared to the Orbscan II (p < 0.01). Adjustment factors for WTW ranged from -0.65 mm to 0.24 mm. Adjustment factors for ACD ranged from -0.21 mm to -0.16 mm. Adjustment factors for CCT ranged from 19.9 µm to -36.0 µm.

Conclusions: The biometers tested were not interchangeable with the Orbscan II. Adjustment factors for WTW and ACD may compensate for differences between devices and adapt ICL sizing recommendations.