Pre- and postoperative refraction after cataract extraction with implantation of standard power IOL.

The pre- and postoperative refraction results are reported in 99 patients receiving an anterior chamber lens of standard 19.0 D power after intracapsular cataract extraction. The mean refraction after the operation was -0.76 D, SD 2.13. Apart from eight patients with suspected lenticular myopia, 5% of the patients ended up with a refraction that differed more than +/- 5D from the preoperative value. This variation was due to variation in the power of the biological lens removed at surgery, the mean value of which was 22.8 D, SD 3.3. As a measure of the aniseikonia induced at surgery, the ocular magnification was calculated to increase 2.7%, SD 4.2%, as compared with the preoperative value. The variation should be considered in the discussion of whether a preoperative biometry and calculation of appropriate IOL power are recommended or not.