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Ryan Barrett, Li Wang, Isi Esquenazi, Mitchell P Weikert, Douglas D Koch; Evaluation of methods to improve the accuracy of IOL calculations in long eyes. Invest. Ophthalmol. Vis. Sci. 2014;55(13):1292.
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© ARVO (1962-2015); The Authors (2016-present)
In eyes with long axial length (AL), current unmodified IOL calculation formulas frequently result in post-operative hyperopia, resulting in a "hyperopic surprise." Optimization of the AL has been proposed to minimize this calculation error. In this study, in eyes with long AL, we evaluated the accuracy of the refractive prediction of 3 IOL calculation formulas after AL optimization and compared those results to the refractive prediction of the standard formulas with the non-modified AL.
Consecutive cases by 1 surgeon of eyes with an AL of > 25mm from April 2010-November 2013 were analyzed; 236 eyes of 166 patients met inclusion criteria. The refractive prediction error (RPE) for each eye was determined by comparing the actual postoperative refraction to the predicted postoperative refraction for the implanted IOL. With the Holladay 1, SRK/T, and Haigis formulas, the predicted refraction was back calculated using both the actual and the optimized AL. P < 0.05 was considered statistically significant.
AL optimization resulted in improved RPE with all 3 formulas, reducing the mean RPE for the Holladay 1 from 0.54 D to 0.09 D, for the SRK/T from 0.36 D to 0.2 D, and for the Haigis from 0.67 D to 0.05 D (all P < 0.001). AL optimization reduced postoperative hyperopic errors by 28.6% for the Holladay 1 formula, 16.7% for the SRK/T formula, and 38.1% for the Haigis formula.
AL optimization for all the tested formulas resulted in a more accurate refractive prediction in eyes with AL > 25 mm and can facilitate more accurate postoperative refractive outcomes after cataract surgery in long eyes.
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