Jack X Kane1, Anton Van Heerden1, Constantinos Petsoglou2
Purpose: To compare the accuracy of novel methods for IOL power selection (Hill-RBF calculator, FullMonte Decision Support System and Ladas “Super Formula”) to newer generation (Barrett Universal 2, Holladay 2, T2) and older generation formulas (Hoffer Q, Holladay 1, Haigis, SRK/T).
Methods: Retrospective analysis of cataract operations over 5 years. Data obtained from the EMR and IOLMaster was entered into the respective calculators. Using optimised lens constants (where possible) the predicted refractive outcome using each of the 10 formulas was calculated and compared to the actual refractive outcome to give the prediction error.
Results: 3168 eyes of 3168 patients were included in the study. A statistically significant difference between the 10 methods for IOL power calculation was found (p<0.001) with the Barrett Universal 2 formula being the most accurate with a mean absolute prediction error (MAE) of 0.382. The "Super Formula" had the 4th lowest MAE, the Hill-RBF the 6th lowest and the FullMonte the highest MAE out of the 10 methods assessed.
Conclusion: Newer methods for predicting the post-operative refraction failed to yield more accurate results than currently used formulas. The Barrett Universal 2 formula is the most accurate formula in eyes over 22.0 mm in axial length.