A comparative analysis of intraocular lens power calculation methods after myopic excimer laser surgery.
To compare the accuracy and predictability of different intraocular lens (IOL) power calculation methods in eyes after myopic excimer laser surgery.



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.



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.



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.
Fam
Han Bor
HB
Eye Institute, Tan Tock Seng Hospital, Singapore.
Lim
Kooi Ling
KL
D001699:Biometry; D006801:Humans; D020731:Keratomileusis, Laser In Situ; D054018:Lasers, Excimer; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008962:Models, Theoretical; D009216:Myopia / Q000601:surgery*; D055095:Optics and Photonics; D018918:Phacoemulsification; D018903:Photorefractive Keratectomy; D012029:Refraction, Ocular; D012030:Refractive Errors / Q000175:diagnosis; D012189:Retrospective Studies; D014792:Visual Acuity