Late post-operative astigmatism after extracapsular cataract extraction and intraocular lens implantation

The purpose of the study is to establish the amount of surgically induced astigmatism after extracapsular cataract extraction (ECCE) and intraocular lens (IOL) implantation. Eighty three eyes of 79 patients who had ECCE + IOL implantation were examined in the period between the 6th and the 16th month after the operation. The pre- and post-operative auto keratometry readings (K1 and K2) were recorded for each patient. These readings were compared between themselves, as well as with the post-operative cylinder power estimated by an autorefractor (total astigmatism). The mean pre-operative corneal astigmatism (K1-K2) was 1.00 +/- 0.09 Dpt Cyl, and the mean post-operative -1.74 +/- 0.14 Dpt Cyl. The difference is statistically significant. The mean autorefractor cylinder power was 1.70 +/- 0.14 Dpt Cyl. It correlates strong with the post-operative corneal astigmatism. There is a moderate correlation between the degree of the post-operative corneal and total astigmatism. The surgically induced corneal astigmatism is the main component of the total post-operative astigmatism after ECCE + IOL implantation. The total astigmatism is mainly with the rule (vertical plus cylinder) and it does not seem to impair severely the post-operative visual acuity of the patients.