Youngsub Eom1, Jong Suk Song1, Yong Yeon Kim1, Hyo Myung Kim2. 1. From the Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea. 2. From the Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea. Electronic address: hyomkim@kumc.or.kr.
Abstract
PURPOSE: To compare the accuracy of the SRK/T and Haigis formulas for predicting corneal astigmatism correction with a toric intraocular lens (IOL). SETTING: Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea. DESIGN: Retrospective cross-sectional study. METHODS: Eyes with an Acrysof toric IOL were enrolled in the study. The corneal plane effective cylinder power of toric IOLs (target induced astigmatism vector [TIA]) predicted by the SRK/T and Haigis formulas were compared with the cylindrical correction achieved postoperatively (surgically induced astigmatism vector [SIA]). The magnitude of error was defined as the difference between the magnitudes of the SIA and TIA. The median absolute magnitudes of error predicted by the SRK/T and Haigis formulas were compared. The median absolute errors predicted by the 2 formulas were also compared. RESULTS: The mean postoperative SIA was 1.80 diopters (D) ± 0.55 (SD). The magnitude of error predicted by the SRK/T and Haigis formulas was 0.31 ± 0.40 D and 0.23 ± 0.40 D, respectively. The median absolute magnitude of error predicted by the Haigis formula was statistically significantly smaller than that predicted by the SRK/T formula (P < .001). The median absolute error predicted by the Haigis formula (0.35 D) was also statistically significantly smaller than that predicted by the SRK/T formula (0.43 D) (P = .003). CONCLUSION: The Haigis formula was more accurate than the SRK/T formula not only in predicting the refractive outcome but also in predicting corneal astigmatism correction by toric IOLs. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.
PURPOSE: To compare the accuracy of the SRK/T and Haigis formulas for predicting corneal astigmatism correction with a toric intraocular lens (IOL). SETTING: Department of Ophthalmology, Korea University College of Medicine, Seoul, South Korea. DESIGN: Retrospective cross-sectional study. METHODS: Eyes with an Acrysof toric IOL were enrolled in the study. The corneal plane effective cylinder power of toric IOLs (target induced astigmatism vector [TIA]) predicted by the SRK/T and Haigis formulas were compared with the cylindrical correction achieved postoperatively (surgically induced astigmatism vector [SIA]). The magnitude of error was defined as the difference between the magnitudes of the SIA and TIA. The median absolute magnitudes of error predicted by the SRK/T and Haigis formulas were compared. The median absolute errors predicted by the 2 formulas were also compared. RESULTS: The mean postoperative SIA was 1.80 diopters (D) ± 0.55 (SD). The magnitude of error predicted by the SRK/T and Haigis formulas was 0.31 ± 0.40 D and 0.23 ± 0.40 D, respectively. The median absolute magnitude of error predicted by the Haigis formula was statistically significantly smaller than that predicted by the SRK/T formula (P < .001). The median absolute error predicted by the Haigis formula (0.35 D) was also statistically significantly smaller than that predicted by the SRK/T formula (0.43 D) (P = .003). CONCLUSION: The Haigis formula was more accurate than the SRK/T formula not only in predicting the refractive outcome but also in predicting corneal astigmatism correction by toric IOLs. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.