[Intraocular lens power calculation after keratorefractive surgery]

ABSTRACT

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