Comparing ultrasound biometry with partial coherence interferometry for intraocular lens power calculations: a randomized study.

Purpose: To determine whether intraocular lens (IOL) power calculations for cataract surgery as measured by postoperative refractive error using partial coherence interferometry (PCI) are more accurate in improving postoperative outcomes than applanation ultrasound biometry (AUS).

Methods: A double-blind randomized controlled trial consisting of 205 patients was undertaken by the Southern Health Ophthalmology Unit, Victoria, Australia. Mean absolute postoperative refractive error (MAE) represented the dependent variable; the biometric technique (PCI; AUS) used to determine the IOL power to be implanted in the surgical eye represented the independent variable. An intention-to-treat analysis was used to prevent loss of randomization caused by the effects of crossover and drop-out.

Results: The MAE in patients with implanted PCI-calculated IOLs was 0.40 +/- 0.37 D (SD; 95% confidence interval [CI], 0.32-0.48 D) compared with 0.45 +/- 0.41 D (SD; 95% CI, 0.36-0.54 D) for patients with implanted AUS-calculated IOLs. There was no statistically significant difference between MAE in patients with implanted PCI-calculated IOLs and that in patients with AUS-calculated IOLs in analysis of best possible outcomes (t(167) = 1.0, P = 0.315).

Conclusions: The results of this trial demonstrated that the calculation of IOL power based on ocular axial length measurement with PCI technology provided no clinical advantage over conventional applanation ultrasound, as measured by postoperative refractive outcome (anzctr.org.au number, ACTRN12608000077369).