Analysis of biometry and prevalence data for corneal astigmatism in 23 239 eyes

PURPOSE: To present and analyze biometry data sets and prevalence data for corneal astigmatism in a large population. SETTING: High-volume eye surgery center, Castrop-Rauxel, Germany. METHODS: Axial length (AL), corneal radii, anterior chamber depth (ACD), and horizontal corneal diameter (white-to-white [WTW] distance) were optically measured by partial coherence interferometry (IOLMaster). Patient data sets acquired between 2000 and 2006 were reviewed and analyzed. RESULTS: The study evaluated 23,239 data sets of 15,448 patients with a median age of 74 years. The mean values were as follows: AL, 23.43 mm +/- 1.51 (SD); corneal radius, 7.69 +/- 0.28 mm; WTW distance, 11.82 +/- 0.40 mm; and ACD, 3.11 +/- 0.43 mm. The ACD and axis of astigmatism were correlated with age. The AL, corneal radius, ACD, and WTW were correlated with one other. Eight percent of eyes had corneal astigmatism greater than 2.00 diopters (D), and 2.6% had more than 3.00 D. Astigmatism was with the rule (WTW) in 46.8% of eyes, against the rule in 34.4%, and oblique in 18.9%. High astigmatism was predominantly WTW. CONCLUSIONS: The results in this analysis might provide normative data for cataract patients and a useful reference for multiple purposes. The correlation of AL with corneal radius, ACD, and corneal diameter in normal eyes was not present in eyes with extreme myopia or hyperopia.