Postoperative astigmatism after intracapsular cataract surgery: results of a randomised controlled trial in Nepal.

PURPOSE: Postoperative astigmatism following intracapsular cataract extraction with or without anterior chamber intraocular lens implantation is reported as an outcome from a randomised controlled trial. METHODS: Five hundred and two of 1002 eyes randomised to intracapsular cataract extraction with anterior chamber intraocular lens (ICCE/AC IOL) and 417 of 998 eyes to intracapsular cataract extraction with aphakic spectacles (ICCE/AS) were seen for objective refraction one year after surgery. The prevalence and axis of astigmatism were evaluated using univariate analysis. Logistic regression was used to compare the postoperative astigmatism between the groups. RESULTS: Acceptable astigmatism (-0.5 to 0.0 DCyl) in the AC IOL group was found in 60 (12.0%) patients (95% CI 9.1%-14.9%) and in the aphakic spectacles group (AS) in 69 (16.5%) patients (95% CI 12.9%-20.1%), moderate astigmatism (-1.0 to-1.5 DCyl) was found in 153 (30.4%) patients (95% CI 26.4-34.6%) in ACIOL group and in 288 (69.1%) patients (95% CI 64.6%-73.6%) in AS group; and large astigmatism (-2.0 to - 8.0 D Cyl) was found in 289 (57.6%) patients (95% CI 53.1%-61.6%) in ACIOL group and in 60 (14.4%) patients (95% CI 11.0% 17.8%) in AS group. Large astigmatism was approximately four times more common in the ICCE/AC IOL group compared to ICCE/AS group. In both groups, most patients had "against-the-rule" astigmatism, 446 (88.8%) (95%CI 86.0%-91.6%) in AC IOL group and 348 (83.5%) (95%CI 79.9%-87.1%) in AS group. CONCLUSION: Astigmatism is common after intracapsular cataract extraction. Insertion of an anterior chamber IOL increases the risk of astigmatism.