* This study was presented as a poster at the 109th Annual Meeting of the Korean Ophthalmological Society 2013.

Purpose: To evaluation the accuracy of the IOL power calculation formulae measured by IOL Master ® and applanation ultra-sonography for the Tecnis ZCB00 IOL Methods: We performed a retrospective study of 170 eyes in 121 patients who underwent cataract surgery in our hospital with AMO Tecnis ZCB00 IOL.s. The SRK/T formula was used to predict the patient’s implanted IOL power. Differences in the pre-dicted refractive errors between IOL Master ® and ultrasonography were analyzed and factors attributed to the differences were also analyzed. Three months after cataract surgery, mean numeric error and mean absolute error were analyzed. Results: SRK/II and SRK/T formulas calculated using ultrasonography showed differences compared to the same formulas cal-culated using IOL Master®, in which hyperopic shift was also demonstrated. No definite factor was attributed to the differences between the 2 methods. Although the 3 formulas of IOL Master ® showed no significant difference in refractive errors, the SRK/T formula calculated using IOL Master ® showed the least mean absolute and numeric errors. Conclusions: IOL Master ® is considered more suitable when determining proper AMO Tecnis ZCB00 IOL power in cataract surgery. The hyperopic shift should be considered when calculating the IOL power using only ultrasonography