The authors investigate the postoperative dioptric deviation from the calculated dioptric power of emetropic intraocular lenses by means of the SRK formula. The deviation varied in 82% of the operated eyes within the range of +/- 1.5 D. More accurate calculations were achieved in a group of eyes with a normal axial length of the eyeball (22.0 to 24.5 mm). The authors discuss also circumstances which influence the accuracy of calculation according to formula SRK (assessment, calculation) and factors participating in the final postoperative refraction (different surgical techniques).