Prevalence of corneal astigmatism before cataract surgery in Chinese patients

PURPOSE: To assess the demographics and distribution of corneal astigmatism before cataract surgery in Chinese patients. SETTING: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China. DESIGN: Clinic-based cross-sectional study. METHODS: From July 2009 to May 2011, preoperative bilateral partial coherence interferometry (IOLMaster) was performed in consecutive patients having cataract surgery. Patient demographics and keratometric data were recorded. RESULTS: The mean age of the 2849 patients (4831 eyes) was 70.56 years +/- 9.55 (SD); there was a predominance of women patients (64.0%). The mean axial length was 23.58 +/- 1.13 mm. The mean corneal astigmatism in this cohort was 1.01 D (range 0.05 to 6.59 D). Corneal astigmatism was between 0.25 D and 1.25 D in 67.7% of eyes, 1.25 D or higher in 27.5% eyes, and less than 0.25 D in 4.8% of eyes. Astigmatism was with the rule in 25.1% of eyes, against the rule (ATR) in 58.2% of eyes, and oblique in 16.7% of eyes. The mean steep keratometry measurement was 44.76 +/- 1.56 D. Against-the-rule astigmatism increased significantly with older age. CONCLUSIONS: Corneal astigmatism largely fell between 0.25 D and 1.25 D in these predominantly elderly female Chinese patients, and ATR astigmatism increased with age.