Changes in Irregular Corneal Astigmatism With Age in Eyes With and Without Cataract Surgery.

Abstract

To investigate the changes in irregular and regular corneal astigmatism with age in eyes that underwent cataract surgery (surgery group) and in eyes that did not undergo surgery (nonsurgery group). We enrolled 120 eyes in each of four age groups in the surgery and nonsurgery groups: (1) 50 to 59 years of age, (2) 60 to 69 years of age, (3) 70 to 79 years of age, and (4) older than or equal to 80 years of age. Eyes in the surgery group underwent videokeratographic examination, at least 6 months postoperatively. Irregular astigmatism components, corneal asymmetry, and higher-order irregularity components were determined using Fourier analysis. The regular astigmatism vector was decomposed into vertical/horizontal (J0) and oblique (J45) components using power vector analysis. Both the mean corneal asymmetry and higher-order irregularity components significantly increased with increasing age in both groups (P < 0.0001). Higher-order irregularity was greater in the surgery group than in the nonsurgery group in all age groups (P ≤ 0.0128). The asymmetry did not differ significantly between groups. Asymmetry and higher-order irregularity were positively correlated with actual age in both the surgery and nonsurgery groups (P < 0.0001). The J0 decreased significantly with age in both groups (P < 0.0001), whereas the J45 did not vary significantly with age. In patients from 50 to 80 years of age who underwent cataract surgery, irregular corneal astigmatism, both the asymmetry and higher-order irregularity components, increased significantly with increasing age, whereas regular astigmatism induces an against-the-rule shift. The higher-order irregularity component persistently increased postoperatively, whereas the asymmetry component did not change significantly.