The precise behavior of the anterior chamber depth after intraocular lens implantation is uncertain. To ascertain variations in the values at different time points, we measured the anterior chamber depth in 38 eyes that had undergone extracapsular cataract extraction and posterior chamber intraocular lens implantation. Measurements were performed by ultrasonography preoperatively and at 2 days, 1 and 2 weeks postoperatively, and at 1-month intervals thereafter up to 10 months (mean follow-up period, 9 months). Results showed that two peaks of the anterior chamber depth occurred at 1 week and 3 months postoperatively (means +/- SD, 3.54 +/- 0.39 and 3.59 +/- 0.43 mm, respectively). A significant difference was found between the values measured preoperatively (3.29 +/- 0.57) and at 2 days postoperatively (3.33 +/- 0.39) and the 1-week postoperative value (p < 0.05, using the one-way analysis of variance test). A significant difference also was found between the preoperative and the monthly measurements and the 3-month postoperative measurement (p < 0.05). We also calculated the refractive error and found that during the second postoperative week, the refraction tended toward higher myopia that became more hyperopic 3 months postoperatively. This anterior chamber depth variation may cause variations in vision after cataract surgery with intraocular lens implantation.