EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/804543
161 EW RESIDENTS April 2017 the effective lens position in fourth generation formulas, it is possible that excluding the lens thickness ad- versely impacted the IOL prediction accuracy of these two fourth genera- tion formulas. Effective toric power is also influenced by the final IOL positioning in the same manner that spherical powers are affected, so the lack of lens thickness data from the IOLMaster may further handicap the fourth generation formulas when be- ing compared to ORA aberrometry. In their discussion, the authors cited just one previous study that suggests lens thicknesses could be excluded without significantly influencing the predictive value of these formulas. 1 More studies are needed to validate this assertion. In this study, the post-operative refractions were performed by a range of different optometrists, not by one single surgeon or surgeon's tive visual acuity was worse than 20/40. They did not explain how many patients were excluded for this reason, nor why the patients had achieved this suboptimal visual acuity. If the post-operative acuity was limited due to other pathology such as macular edema, this should be clearly stated. On the other hand, if the acuity was limited due to erroneous predictions for the IOL power, then the eyes should not have been excluded from the study. The authors also excluded eyes with unreliable biometry data but did not specify how they defined unreliable biometry data, nor how many eyes met this criterion. The authors state that the lens thickness was not included in the formulas produced by the IOLMas- ter 500 (Carl Zeiss Meditec, Jena, Germany), the Holladay 2, and Barrett Universal II. Since the lens thickness is important for estimating Selection in Axial Myopes" continued on page 162 " The merits of intraoperative aberrometry have been previously validated in post-refractive surgery patients. Additionally, the ORA can guide the positioning of the toric IOL implants and, therefore, it is useful for improving the surgeons' confidence with toric lenses. We agree with this study's recommendation to also evaluate the merit of the ORA and the AL-optimized Holladay 1 in axial hyperopia and keratoconus. "