Purpose: Our aim was to evaluate the reliability of IOLMaster (Zeiss, Germany) in calculation of intraocular lens (IOL) power in subjects who will have phacoemulsification surgery and the relationship between the refractive deviation and the axial length.

Materials and Methods: The study included 80 patients (58 men, 22 women) who has uncomplicated phacoemulsification surgery and intracapsular hydrophobic acrylic IOL (Acrysof SA60AT, Alcon®) implantation. Before the surgery, a detailed ophthalmological examination was done and the IOL power was calculated with IOLMASTER using SRK II formula. The absolute error, which is the difference between target spherical equivalent (SE) and postoperative 1st month SE was calculated. Multifocal logistic regression analysis was done to evaluate the relationship of absolute error with age, axial length, mean keratometry, anterior chamber depth and preoperative astigmatism. A p value less than 0.05 was accepted as statistically significant.

Results: The mean age of the patients was 65.80±11.15 years (24-85 years). The mean axial length was 23.63±0.76 mm (range 22-25 mm) and mean keratometry value was 43.53±1.56 D. Postoperative refraction deviated from expected values -0.92 D and +1.27 D and the mean absolute error was 0.43±0.31 D. Deviation from target refraction was ≥+0.50D in 20% of the subjects, between +0.50 and -0.50 D in 68.75% of the subjects, and < -0.50 D in 11.25% of the subjects. Refraction deviation was between +1 D and -1 D in 87.5% of the subjects. In multifocal logistic regression analysis, no relationship could be found between absolute error, age, axial length, mean keratometry and anterior chamber depth (p>0.05), whereas there was a significant relationship between absolute error and preoperative astigmatism (t=-2.25) (p=0.027).

Conclusions: The measurements taken with IOLMaster is very reliable. The refractive deviation from target value is very small in subjects with axial length between 22–25 mm.