IOL Master 500 from ZEISS is teh gold standard in optical biometry. The device provides accurate and fast measurements of the axial length, corneal keratometries, Anterior Chamber Depth (ACD). The accuracy of the above-mentioned data is crucially important for the success of the refractive surgery. Various formulas are integrated into the device which enable accurate IOL power calculations for cataract surgery with individual approach in each clinical case.