Intraocular lens power calculation after corneal refractive surgery using serf-designed computer software programmed with optimized calculation method

Abstract

Objective To evaluate intraocular lens power calculation after laser refractive surgery using an optimized calculation method and self-designed computer software. Methods Intraocular lens power calculation method was optimized in the following aspects: corrective algorithm for corneal power estimation; algorithm for effective lens position estimation and double-K method for intraocular lens power calculation; and standardized formula for intraocular lens power calculation.The calculation method was programmed into self-designed computer software (IOL calculator for post-refractive cases). Forty-nine eyes after eximer-laser corneal refractive surgery were retrospectively studied. Intraocular lens power and calculated postoperative refraction were calculated by the optimized method using the computer software. The difference between calculated postoperative refraction and actual postoperative refraction (prediction error) and absolute prediction error were analyzed by SPSS 11.0 software. Results Mean postoperative refraction was (-0.78±0.83)D (-2.50～0.75 D). Three eyes (6.1%) were emmetropic, 36 eyes (73.5%) were myopic, 10 eyes (20.4%) were hyperopic. Mean prediction error was (-0.02±0.75)D(-1.26～1.96 D). Mean absolute prection error was (0.62±0.42)D(0～1.96 D), 19 eyes (38.8%) were ≤0.5 D, 22 eyes (44.9%) were ＞0.5 D and ≤1.0 D,7 eyes (14.3%) were ＞1.0 D and ≤1.5 D, 1 eye (2.0%) was ＞1.5 D and ≤2.0 D. No eye was higher than 2.0 D. Conclusion The computer software programmed with optimized calculation method is a reliable solution to the intraocular lens power calculation after laser corneal refractive surgery. Key words: Lenses,intraocular; Power calculation; Lasers,excimer; Corneal refractive surgery; Computer software