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 analyzed retrospectively. Target refractions based on actual and refraction-derived keratometric values were compared with postoperative achieved refractions. The target refractions calculated using 5 IOL formulas and 2 A-constants 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-derived keratometric value was used to calculate the IOL power. The difference between target and achieved refractions appeared smaller when the Binkhorst formula was used. No significant hyperopic shift was observed after cataract surgery. Conclusion: The smaller of the actual or the refraction-derived keratometric value is recommended for calculating IOL power in post-PRK eyes. J Cataract Refract Surg 2000; 26:1147-1151 (C) 2000 ASCRS and ESCRS.