Optimizing IOL Power Calculations in Eyes With Axial Lengths Above 25.0 mm in an Asian Population
Purpose
To evaluate the accuracy of refractive prediction of 5 intraocular lens (IOL) power calculation formulas in eyes with axial length (AL) greater than 25.0 mm.
Methods
Refractive prediction errors with the Holladay 1, Haigis, SRK/T, Hoffer Q and Barrett Universal II formulas were evaluated in consecutive cases. Eyes with AL greater than 25.0mm underwent uncomplicated phacoemulsification and intraocular lens implantation by 2 surgeons. Their results were compared both for axial lengths that were from IOL Master and axial length that were optimized, except for Barrett Universal II formula.
Results
By optimizing AL, reduced the mean numerical errors for Holladay 1 formula + 0.36 D to -0.02 D, Haigis formula +0.19D to -0.17 D , SRK-T formula +0.10D to -0.25D and Hoffer Q +0.48 to +0.11. For Barrett Universal II formula +0.11D to -0.24D. Amongst the formula optimized AL using the Haigis formula has the lowest mean absolute error and refractive predictive error.
Conclusion
The proposed method of optimizing AL significantly reduced the percentage of long eyes with a hyperopic outcome in all formulas. Barrett Universal II formula reduces mean numerical error without optimization of axial length.