Accuracy of IOL Calculations in Post Corneal Refractive–Surgery Eyes
To evaluate outcomes for intraocular lens (IOL) power calculations after corneal refractive surgery (LASIK and PRK) and determine the most accurate method for each, including myopic and hyperopic corrections.
Retrospective analysis of 42 eyes (26 patients) with uneventful cataract extraction after LASIK (40 eyes) or PRK (2 Eyes) from January 2012 to June 2014 by one surgeon (JBR). Analysis included final UDVA, CDVA, MRSE, and absolute deviation from target refraction. Calculation formulas compared included those available through the ASCRS calculator and an Optimized K-Holladay 2 formula.
Average final UDVA was ~20/30 (logMAR 0.15) for the 29 eyes corrected for distance. Average CDVA was ~20/23 (logMAR 0.06) for the 35 eyes with postop refractions. Postop MRSE for eyes targeted for distance (n = 29) was -0.06 diopters, for intermediate distance (n = 9) was -1.13 diopters, and for near (n = 4) was -2.16 diopters. An optimized keratometry value was utilized in the Holladay 2 formula to determine the Optimized K-Holladay 2 IOL calculation. For hyperopic and myopic post corneal refractive patients, the Optimized K-Holladay 2 method was the most accurate IOL power calculation when compared to the other available IOL power calculations. For hyperopic eyes, Haigis was more accurate than Shammas. However for myopic eyes the Shammas method was more accurate followed by Haigis and Wang-Koch-Maloney.
The Optimized K-Holladay 2 method seems to be the most accurate IOL power calculation method in post laser corneal refractive surgery patients irrespective of type of ablation done.