Intraocular Lens Power Calculation after Corneal Refractive Surgery

Purpose: to report refractive outcomes following phacoemulsification (pe) and posterior chamber intraocular lens (pciol) implantation in eyes with previouscorneal refractive surgery. methods: in this retrospective comparative study, 18 consecutive eyes of 14 patients with previous keratorefractive surgery for myopia including photorefractive keratectomy (prk, 6 eyes; 33.3%) and laser in situ keratomileusis (lasik, 12 eyes; 66.7%) underwent pe+pciol. computerized corneal topography was employed to determine the flattest keratometric reading within the 3-mm central zone. this value was inserted into the sanders-retzlaff-kraff/t (srk/t) formula to calculate iol power. iol power selected for implantation was 1 d greater than the calculated value described above. results: mean age and follow-up period were 54.1±11.5 years and 29.9±26.3 months, respectively. mean implanted lens power was 18.56±3.86 d which was not significantly different from mean back-calculated iol power for target refraction (19.04±4.16 d)(p=0.28). there was no significant difference between mean target refraction (-0.94±0.52d) and achieved postoperative spherical equivalent refractive error (-0.62±1.06) at final follow-up (p=0.28). the achieved spherical equivalent refractive error was within ±0.50 d of intended refraction in 8 (44.4%) eyes, within ±1.0 d in 11 (61.1%) eyes, and within ±2.0 d in 16 (88.9%) eyes. in a subgroup of patients (5 eyes) with complete pre-refractive surgery data, the difference between post-refractive surgery keratometry method and all other methods (p=0.02) and between the current method and the feiz-mannis method (p=0.01) was statistically significant. conclusion: the method suggested herein is simple and independent of pre-refractive surgery data with results comparable to other commonly used methods