Comparison of prediction error: Labeled versus unlabeled intraocular lens manufacturing tolerance

PurposeTo compare the prediction error between intraocular lenses (IOLs) available in 0.25 diopter (D) increments with a labeled manufacturing tolerance and IOLs available in 0.50 D increments without a labeled manufacturing tolerance.SettingCommunity-based multidisciplinary outpatient ophthalmic practices.DesignComparative case series.MethodsEyes with cataract had implantation of an IOL available in 0.25 D increments and labeled with a manufacturing tolerance of ±0.11 D (labeled group) or an IOL available in 0.50 D increments without a labeled manufacturing tolerance (unlabeled group). Postoperatively, the prediction error was calculated and compared between groups.ResultsBy the SRK/T formula, the mean error of prediction after optimization was −0.03 D ± 0.35 (SD) in the labeled group and −0.05 ± 0.46 D in the unlabeled group (P=.64). The mean absolute error of prediction was statistically significantly smaller in the labeled group (0.26 ± 0.23 D) than in the unlabeled group (0.37 ± 0.28 D) (P=.04). The mean and absolute errors were not statistically significantly different with the Holladay 1 or Hoffer Q formula. Sixty-three percent of patients in the labeled group and 43% in the unlabeled group (P=.03) were within ±0.25 D of the prediction error; 84% and 69%, respectively, were within ±0.50 D (P=.06).ConclusionThe IOLs available in 0.25 D increments with a labeled manufacturing tolerance of ±0.11 D increased the percentage of patients within ±0.25 D of the targeted refraction to a statistically significant and clinically meaningful level compared with unlabeled IOLs available in 0.50 D increments.Financial DisclosureNo author has a financial or proprietary interest in any material or method mentioned.