Abstract
Abstract: :
Purpose: To compare the predictive accuracy of post-operative refraction using the Holladay 2 versus the Holladay 1 IOL power formula in eyes with excessively flat or steep keratometry readings or excessively long or short axial lengths. Methods: This prospective analysis involved the selection of 18 pre-operative eyes with unusual corneal curvatures or axial lengths. Patients had average K values of less then 42.00 D or greater than 46.00 D. Alternatively, axial length measurements were less then 22.0 mm or greater than 26.0 mm. The implanted intraocular lens was then chosen based upon the Holladay 2 IOL power formula. Holladay 1 predictive data was also gathered for each eye. Uncomplicated cataract surgery with implantation of the same style intraocular lens was then performed. Post-operative refractions were taken on three occasions and an average spherical equivalent determined. Holladay 1 and 2 predicted post-operative refractions (spherical equivalent) were then compared to the actual post-operative refractions (spherical equivalent). Results: The mean absolute deviation (MAD) between the actual post-operative manifest refraction and predicted post-operative refraction was slightly higher for the Holladay 2 formula versus the Holladay 1 formula (0.487 D vs. 0.409 D). Using either formula, the predicted post-operative refraction was relatively hyperopic 44% of the time (MAD 0.56 D Holladay 2 and 0.37 D Holladay 1) and relatively myopic 56% of the time (MAD 0.43 D Holladay 2 and 0.44 D Holladay 1). Conclusion: Although the Holladay 2 formula is intended to provide clinically superior predictive accuracy for patients with extreme axial lengths or keratometry readings, this was not evident in the refractive outcomes of our patient population.
Keywords: 609 treatment outcomes of cataract surgery • 543 refractive error development • 338 cataract