Compiled by Callan Navitsky, Associate Editor, and Steve Daily, News Editor
Intraocular lenses (IOLs) available in 0.25 D increments with a labeled manufacturing tolerance significantly increased the percentage of patients achieving a refraction within ±0.25 D of the target. This improvement was statistically significant and clinically meaningful compared to unlabeled IOLs available in 0.50 D increments, according to a study published in the Journal of Cataract & Refractive Surgery.
In the study, 118 eyes underwent cataract surgery with IOL implantation. Of these, 67 eyes received IOLs available in 0.25 D increments with a labeled manufacturing tolerance of ±0.11 D, while 51 eyes received IOLs available in 0.50 D increments without a labeled manufacturing tolerance.
Using the SRK-T formula, the mean prediction error after optimization was -0.03 ±0.35 D (standard deviation) in the labeled group and -0.05 ±0.46 D in the unlabeled group (P=.64). The mean absolute prediction error was significantly smaller in the labeled group (0.26 ±0.23 D) compared to the unlabeled group (0.37 ±0.28 D; P=.04). The differences in mean and absolute errors were not statistically significant when using the Holladay 1 or Hoffer Q formulas. In terms of prediction accuracy, 63% of patients in the labeled group and 43% in the unlabeled group (P=.03) were within ±0.25 D of the prediction error, while 84% and 69% respectively, were within ±0.50 D (P=.06).
Source: Zudans JV, Desai NR, Trattler WB. Comparison of prediction error: labeled versus unlabeled intraocular lens manufacturing tolerance. J Cataract Refract Surg. 2012;38(3):394-402.