Accuracy of Intraocular Lens Power Calculations According to Corneal Curvature in Short Eyes

ABSTRACT

PURPOSE: To evaluate the accuracy of intraocular lens (IOL) power calculations between Hoffer Q and other formulas according to corneal curvature by comparing the results of cataract surgery and calculation of chosen formulas in short axial lengths. METHODS: We performed a retrospective analysis of patients who underwent cataract surgery from January 1st, 2012 to June 12th, 2012. The patients were selected if their axial length was below 23.00 mm and 77 patients (90 eyes) were included in the present study. The patients were divided into 2 groups according to mean corneal curvature below 44.0 D and over 45.0 D. IOL power was calculated using the Hoffer Q and SRK II, SRK-T and Holladay I formulas and the error between the calculations and refractive outcome of cataract surgery were measured. The accuracy of each formula was evaluated by comparing the error between the 2 groups. RESULTS: Hoffer Q formula showed a higher predictive accuracy than other formulas regardless of corneal curvature in eyes with short axial lengths (p < 0.001, p = 0.023). Particularly, SRK II, SRK-T and Holladay I showed a lower predictive accuracy in eyes with flat corneal curvature than Hoffer Q (p < 0.001, p = 0.215). CONCLUSIONS: In eyes with short axial lengths, preoperative predicted IOL power calculations showed better accuracy with Hoffer Q formula than SRK II, SRK-T and Holladay I formulas. SRK II, SRK-T and Holladay I formulas showed a lower predictive accuracy in flat corneal curvature eyes than steep corneal curvature eyes with short axial lengths. We hypothesize that SRK II, SRK-T and Holladay I tend to underestimate effective lens position in eyes with short axial lengths indicating Hoffer Q formula is more accurate.