Eyeworld

EW RESIDENTS 160 April 2017 by Atalie C. Thompson, MD, MPH, Daniel Vu, MD, Morgan Godin, MD, Pratap Challa, MD T his retrospective case series of 51 eyes seeks to compare the refractive outcomes when an intraocular lens (IOL) was selected based on either intraoperative aberrometry (ORA, Alcon, Fort Worth, Texas) or the new Hill-RBF formula versus other third and fourth generation preoperative biometry formulas such as SRK/T, Holladay 1, Holladay 2, and Barrett Universal II, as well as the axial length-optimized equation using the Wang-Koch adjustment. Because current formulas are less accurate in selecting IOLs for sub- jects with axial myopia, and because neither the ORA nor the Hill-RBF have been studied in myopes, the study focused on patients whose axial length (AL) exceeded 25 mm. Primary outcomes included differ- ences between predicted and actual postoperative spherical equivalent (SE) and percentages of patients who were within 0.5 D and 1 D of their target refractions. Postoperative refractions, performed between 21 and 60 days after surgery, were com- pared against the seven prediction methods to determine the difference in mean numerical errors or median numerical errors. This study con- cluded that ORA performed similarly to the AL-optimized Holladay 1 formula and both were better than the other prediction methods for determining residual refractive error and reducing hyperopic outcomes in this specific population. This study also concluded that the Hill-RBF held up against the fourth genera- tion formulas, but was less accurate than ORA or AL-optimized Holladay 1. The study has many merits, but could be enhanced with some clari- fications regarding the methodology and analysis. Methods The methods section states that 51 eyes were enrolled in this study, but does not specify whether the eyes were from 51 different patients or from fewer than 51 patients. If the latter, then the authors should clarify whether any adjustment was made to account for the fact that two eyes from the same patient are not independent from each other. The sample size was small, and all surgeries were performed by a single surgeon which may limit external generalizability. Furthermore, the authors excluded eyes whose post-opera- Review of "Intraoperative Aberrometry versus Preoperative Biometry for Intraocular Lens Power Pratap Challa, MD, ophthalmology residency program director, Duke Ophthalmology, Duke University School of Medicine, Durham, North Carolina IOL selection in high myopes is challenging. Intraoperative wave- front aberrometry and a number of new formulae have been developed with the goal of improving our ac- curacy. I asked the Duke residents to review this study comparing these newest modalities in the current issue of JCRS. –David F. Chang, MD, EyeWorld journal club editor EyeWorld journal club From left: Daniel Vu, MD, Atalie Thompson, MD, MPH, Morgan Godin, MD Source: Amy Tong, MD

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