Clinical assessment of the Zeiss IOLMaster

Purpose: To compare axial lengths and intraocular lens (IOL) power calculations obtained with the Zeiss IOLMaster(R) by 2 observers with different training grades and to assess the agreement between optical and acoustic biometry. Setting: Department of Ophthalmology, Pembury Hospital, The Laser Eye Clinic, Kent, United Kingdom. Methods: In this prospective study, optical biometry was performed twice in 79 patients: first by a qualified ophthalmic nurse and second by 1 of several health care assistants without formal nursing training. In the same group of patients, the qualified nurse also obtained ultrasonic measurements to compare the 2 clinical methods. Results: There was a high correlation coefficient for axial length and IOL power measurements (0.99 each) between the experienced examiner and the inexperienced examiners. The coefficient of repeatability (2 SD) was 0.58 diopter (D) for IOL power (mean 0.04 D) and 0.07 mm for the axial length (mean 0.00 mm). The correlation coefficient of IOLMaster measurements with A-scan measurements done by the same experienced ophthalmic nurse was 0.97 for IOL power and 0.98 for axial length. The limits of agreement (mean +/- 2 SD) were between +0.50 and -2.40 D for IOL power calculations and between +0.7 mm and -0.2 mm for axial length measurements. Conclusions: Optical biometry showed excellent repeatability using different examiners regardless of their medical training. The agreement with ultrasonic measurements and the precision of the method need further evaluation.