Comparing immersion ultrasound with partial coherence interferometry for intraocular lens power calculation.

BACKGROUND AND OBJECTIVE: To compare the utility and accuracy of high-precision immersion ultrasound, partial coherence interferometry, and the IOL Master system (Carl Zeiss Meditec, Dublin, CA) in a tertiary care referral center. PATIENTS AND METHODS: Comparative clinical study in a tertiary care, multispecialty, university practice. Participants were consecutive patients scheduled for cataract surgery at Emory Eye Center. Patients underwent biometry using immersion ultrasound, partial coherence interferometry, and the IOL Master system. RESULTS: Twenty-two percent of eyes undergoing surgery could not be measured using interferometry. In those eyes measurable by both methods, there was no difference in measurements nor postoperative refractive outcome. Each method had a high repeatability (intraclass correlation coefficient > 0.99) with a high intraclass correlation between methods (intraclass correlation coefficient = 0.99). CONCLUSIONS: When it can be used, interferometry is equivalent to immersion ultrasonography regarding biometric accuracy and precision. However, it cannot replace ultrasonography, especially for eyes with dense media opacity.