Comparison of Hoffer Q and Haigis formulae for intraocular lens power calculation according to the anterior chamber depth in short eyes.

PURPOSE: To compare the accuracy of the Hoffer Q and Haigis formulae according to the anterior chamber depth (ACD) in cases of short axial length (AL). DESIGN: Retrospective cross-sectional study. METHODS: A total of 75 eyes from 75 patients with an AL of less than 22.0 mm implanted with an Acrysof IQ intraocular lens (IOL) were enrolled. The median absolute errors (MedAEs) predicted by the Hoffer Q and Haigis formulae were compared. The correlations between ACD and the predicted refractive error calculated using the 2 formulae were analyzed. RESULTS: There were no significant differences in the MedAEs predicted by the Hoffer Q and Haigis formulae (0.40 and 0.40 diopter [D], respectively). The difference between the refractive errors predicted by the Hoffer Q and Haigis formulae increased significantly as the ACD decreased (R(2) = 0.644, P < .001). The MedAE predicted by the Haigis formula (0.40 D) was significantly smaller than that predicted by the Hoffer Q formula (0.66 D) in eyes with an ACD of less than 2.40 mm (P = .027). There were no significant differences found between the MedAEs predicted by the Hoffer Q and Haigis formulae in eyes with an ACD of 2.40 mm or more. CONCLUSIONS: The differences between the predicted refractive errors of the Hoffer Q and Haigis formula increased as ACD decreased in short eyes. Therefore, ACD should be taken into consideration when evaluating the accuracy of the IOL power calculation formulae in short eyes.