PURPOSE
To compare the accuracy and predictability of different intraocular lens (IOL) power calculation methods in eyes after myopic excimer laser surgery.
METHODS
Phacoemulsification and IOL implantation outcomes in 37 eyes of 37 patients with prior LASIK or photorefractive keratectomy were documented (amount of correction=–6.92±3.12 diopters (D), range: –2.00 to –13.00 D). The theoretical IOL power that would have resulted in emmetropia was calculated (IOLemme). Using the clinical history keratometry and biometry, the IOL power was calculated using the following methods: Sanders, Retzlaff, Kraff (SRK)-T, SRK-T Double-K (DK), Holladay 1 DK, Hoffer Q DK, Holladay 2 DK, Feiz-Mannis, and Ladas-Stark corneal bypass. The calculated IOL power was compared to IOLemme and used to determine the mean error and mean absolute error of refractive outcome for each eye.
RESULTS
The calculated IOL power using the SRK-T, Feiz-Mannis, and Holladay 1 DK methods were significantly different from IOLemme. The lowest mean absolute error was achieved using the Hoffer Q DK method (0.75±0.52 D), Holladay 2 DK (0.75±0.62 D), SRK-T DK (0.76±0.60 D), and Ladas-Stark (0.83±63 D). With the SRK-T DK method, 51.4% of eyes were within ±0.50 D of emmetropia and 67.6% of eyes were within ±1.00 D. The Holladay 2 DK method had the highest percentage (81.1%) of eyes within ±1.00 D and 45.9% within ±0.50 D.
CONCLUSIONS
The refractive results of IOL implantation using the same biometry data in eyes after LASIK can vary markedly. The SRK-T DK, Hoffer Q DK, and Holladay 2 DK methods resulted in the highest accuracy.