Accuracy and predictability of intraocular lens power calculation after photorefractive keratectomy

Purpose: To investigate the accuracy and predictability of intraocular lens (IOL) power calculation in postoperative photorefractive keratectomy (PRK) eyes. Setting: Gimbel Eye Centre, Calgary, Alberta, Canada. Methods: The results in 5 cataract surgery eyes that had had PRK were analy zed retrospectively. Target refractions based on actual and refraction-deri ved keratometric values were compared with postoperative achieved refractio ns. The target refractions calculated using 5 IOL formulas and 2 A-constant s were also compared with the achieved refractions. Results: In postoperative PRK eyes, the power calculation was more accurate and predictable when the smaller of either the actual or refraction-derive d keratometric value was used to calculate the IOL power. The difference be tween target and achieved refractions appeared smaller when the Binkhorst f ormula was used. No significant hyperopic shift was observed after cataract surgery. Conclusion: The smaller of the actual or the refraction-derived keratometri c value is recommended for calculating IOL power in post-PRK eyes. J Catara ct Refract Surg 2000; 26:1147-1151 (C) 2000 ASCRS and ESCRS.