The Accuracy of Intraocular Lens Power Calculation for Cataract Surgery after Laser in Situ Ketatomileusis

Abstract

PURPOSE: To investigate the accuracy of several different methods for intraocular lens power calculation after laser in situ keratomileusis. SUBJECTS AND METHODS: Axial length, corneal radius and anterior chamber depth of 11 eyes in 9 cases of cataract surgery after myopic or myopic astigmatic laser in situ keratomileusis were measured by IOL MasterTM (Carl Zeiss Meditec) for Haigis-L formula. For Double-K method by Aramberri and his group, Holladay II formula and No-history method by Shammas and his group, corneal radius of these 11 eyes were measured by ARK-700A (NIDEK) and anterior chamber depth were measured by AL-2000 (TOMEY). To compare the error between predicted refraction and postoperative refraction which was obtained from the implanted intraocular lens power required parameters were applied to each formula. The mean age when the cataract surgery was performed: 52.6•}9.0. The mean axial length: 26.43•}2.20mm. RESULTS: The mean absolute errors between the predicted refraction and the refraction of after cataract surgery and the percentages that the error was within •}1.0D with each calculation: DK method: 1.18•}0.86D (45.5%), Holladay II formula: 0.93•}0.61D (63.6%), No-history method: 0.74•} 0.60D (54.5%), Haigis-L formula: 0.85•}0.70D (63.6%). CONCLUSION: Difference was found in these 4 intraocular lens power calculations after laser in situ keratomileusis. With Haigis-L formula, the percentage that the error between predicted refraction and the refraction of after cataract surgery was within •}1.0D was high and the error was small. With every calculation, in the case of eyes with long axial length, we found a tendency of myopic shift. For clinical application, including the evaluation of corneal refractive power after LASIK, close further fully examination into each characteristic of these calculations will be required.