The accuracies of intraocular lens (IOL) power calculation formulas in short-length eyes

Abstract

Objective To explore the accuracies of intraocular lens(IOL) power calculations by using 6 formulas ( SKT,HAIGIS,HOFFER-Q,SRK-Ⅱ,HOLLADAY,BKINK-Ⅱ) in Chinese short eyes.Methods Data were prospectively collected by identifying eyes of axial length below 22 mm.The axial lengths and keratometry of the 32 short eyes were measured with ultrasonic scanning before operation,and the actual postoperative refraction was measured with the methods of computer and retinoscopy optometry when patients could gain best corrected visual acuity one month after surgery or later.Inputting the axial lengths,keratometry and IOL powers into ultrasonic scanning,the predicted postoperative refraction was calculated with 6 formulas,and differences of predicted and actual postoperative refraction in short eyes were compared.The absolute refraction errors were the absolute value with the difference of the predicted and actual postoperative refraction.Results The differences of the absolute refraction errors were compared,there were no significant differences among 5 formulae except HAIGIS in the short eyes.Absolute refraction errors of the SRK-Ⅱ and SKT were smaller than other formulae.The distribution rate of the absolute refraction errors in the SKT formula was the largest from 0 to 0.50 D in Chinese short eyes.Conclutions The SKT formula provides the best predictive result of the absolute refraction errors from 0 to 0.50 D in Chinese short eyes.The HAIGIS is the least accurate in 6 formulae in Chinese short eyes. Key words: Phacoemulsification; Lens,intraocular; Eye,short-length