To develop a correcting term for intraocular power (IOLP) prediction for penetrating keratoplasty combined with simultaneous extracapsular cataract extraction and posterior chamber lens implantation (triple procedure).As part of a prospective clinical study, triple procedures were performed in 42 eyes with Fuchs' dystrophy. Only eyes with readable preoperative K-values were included in this study. Differences (DEV) between achieved and target refraction (TR) depending on the values of the theoretical-optical formula according to HAIGIS were investigated using multiple regression analysis in a linear anova model: DEV = a + b CP + c AL + d IOLP + e TR. CP represents central corneal power, AL represents axial length.Spherical equivalent after suture removal was - 1.39 +/- 2.86 D (TR: - 1.64 +/- 1.72 D). A multiple regression formula was developed for correction of conventionally calculated IOL power. CP (b = - 1.391, p = 0.028), AL (c = - 4.733, p = 0.007), IOLP (d = - 1.301, p = 0.009) and TR (e = - 1.804, p = 0.005) correlated significantly with DEV (a = 198.684).Proposed correcting multiple regression formula for IOL power prediction may help to improve the postoperative refractive outcome in patients undergoing triple procedures.