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

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.

Accuracy of Intraocular Lens Power Calculations According to the Formulas and Anterior Chamber Depth in Short Eyes

PURPOSE: To evaluate the accuracy of intraocular lens (IOL) power calculations according to the chosen formulas and anterior chamber depths in eyes with short axial lengths. METHODS: A retrospective analysis was performed on 57 eyes of 50 patients (axial length < 22.0 mm) and 42 eyes of 36 patients (22.0 mm < or = axial length < 25.0 mm) who underwent cataract surgery. IOL power was calculated with the SRK II, SRK/T, Binkhorst, Holladay I, and Hoffer Q formulas. The differences between the predicted refraction and the actual refraction were compared and analyzed. The errors according to the anterior chamber depth were also evaluated. RESULTS: The SRK II formula showed a lower predictive accuracy, and the other formulas showed similar accuracies in eyes with short axial lengths. The Holladay 1 and Hoffer Q formulas showed good predictive accuracies in eyes with short axial lengths. Hyperopic shift tended to occur with all formulas in eyes with short axial lengths. When using SRK II and SRK/T formulas, a correlation between axial length and hyperopic shift was observed, with shorter axial length patients shifting to more hyperopic conditions. In eyes with short axial lengths, larger hyperopic shifts tended to occur in eyes with relatively deeper anterior chambers. CONCLUSIONS: In eyes with short axial lengths, preoperative predicted IOL power showed good accuracies with Holladay 1 and Hoffer Q formulas. Preoperative anterior chamber depth and axial length had a strong influence on the accuracies of predicted IOL power.