Intraocular Lens Power Calculation after Keratorefractive Surgery

To determine corneal power for intraocular lens (IOL) power calculation in eyes with previous keratorefractive surgery. In 13 eyes of 9 patients with previous keratorefractive surgery undergoing phacoemulcification, IOL power was calculated using the clinical history method (CHM) in one case, manual keratometry (MKR) in 2, SimK in 3, and flattest K (topographically derived) in 7 cases. SRK-T formula with applanation method was used. Final refractions (SE) are presented. Patients included 7 male and 2 female subjects aged 51.2±9.3 (range 41-70 years). Postoperative refraction was hyperopic (+1.5 D) in eyes with the CHM, variable and unpredictable in cases with the MKR and SimK and more desirable (-0.35±0.39 D) in cases of flattest K. In this latter group the best postoperative refraction was achieved in cases which 0.5 to 1.00 D was added to the calculated IOL power. It seems using topographically derived flattest K for IOL power calculation and adding 1.00 D to the calculated IOL power in eyes with previous myopic-refractive surgery, and using the steepest K together with subtracting 1.00 D from the calculated IOL power in eyes with previous hyperopic-refractive surgery is useful when pre-refractive surgery data are not available.