Effect of pharmacological pupil dilation on measurements and iol power calculation made using the new swept-source optical coherence tomography-based optical biometer.

PURPOSE

To determine whether pupil dilation affects biometric measurements and intraocular lens (IOL) power calculation made using the new swept-source optical coherence tomography-based optical biometer (IOLMaster 700; Carl Zeiss Meditec, Jena, Germany).

PROCEDURES

Eighty-one eyes of 81 patients evaluated for cataract surgery were prospectively examined using the IOLMaster 700 before and after pupil dilation with tropicamide 1%. The measurements made were: axial length (AL), central corneal thickness (CCT), aqueous chamber depth (ACD), lens thickness (LT), mean keratometry (MK), white-to-white distance (WTW) and pupil diameter (PD). Holladay II and SRK/T formulas were used to calculate IOL power. Agreement between measurement modes (with and without dilation) was assessed through intraclass correlation coefficients (ICC) and Bland-Altman plots.

RESULTS

Mean patient age was 75.17±7.54 years (range: 57-92). Of the variables determined, CCT, ACD, LT and WTW varied significantly according to pupil dilation. Excellent intraobserver correlation was observed between measurements made before and after pupil dilation. Mean IOL power calculation using the Holladay 2 and SRK/T formulas were unmodified by pupil dilation.

CONCLUSIONS

The use of pupil dilation produces statistical yet not clinically significant differences in some IOLMaster 700 measurements. However, it does not affect mean IOL power calculation.