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To determine the effects of contact lens (CL) wear on biometry measurements for cataract surgery and whether a CL hiatus can reduce the prediction error of intraocular lens (IOL) calculations.Retrospective, interventional case series of eyes that received repeat biometry measurements for IOL calculations after discontinuing hard or soft CLs for at least 14 days. Primary outcome measures: intersession change in axial length, average keratometry, astigmatism, and axis. Secondary outcome measures: change in recommended IOL power and toricity, postoperative refraction prediction error.Thirty-two eyes of 16 patients had a mean duration of CL wear (12 hard and 20 soft) of 39.5 years (range, 29–55 years) and mean CL hiatus duration of 25 days (range, 14–56 days). Mean absolute intersession change in axial length was 0.016 mm (range, 0–0.05 mm), average keratometry 0.31 D (range, 0.02–1.01 D), astigmatism 0.41 D (range, 0.01–1.10 D), and axis 6.3° (range, 0–28°). The IOL power predicting the lowest postoperative spherical equivalent changed for 17 of 32 eyes (by 0.5 D for 12 eyes and 1.0 D for five eyes). Recommended IOL toricity changed for nine of 14 eyes (by 0.75 D for six eyes and 1.50 D for three eyes). The median absolute prediction error of IOL calculations was 0.69 D (range, 0.19–2.93 D) before and 0.57 D (range, 0.01–2.82 D) after the CL hiatus (P=0.16).Contact lens wear may affect biometry measurements and subsequent IOL power and toricity selection. For some eyes, repeating biometry measurements after a CL hiatus may improve the accuracy of IOL calculations.