[Investigation of corneal astigmatism in phacoemulsification surgery candidates with cataract]

To investigate the characters of corneal astigmatism in cataract surgery candidates.

IOLMaster 5.0 was adopted in this study to measure preoperative corneal keratometry. The first suffered eye was taken as the observed eye when both eyes were involved. Descriptive statistics of keratometric cylinder data were analyzed. The mean of corneal astigmatism, distribution of astigmatism and the cumulated distribution were calculated. The relationship between age, axial length and astigmatism was analyzed respectively. The symmetry of binocular astigmatism was also studied.

Preoperative keratometric data were obtained from 1389 patients (1389 eyes) with age related cataract (mean age 67.75 years, range from 40 to 79 years). The median of astigmatism was 0.84 D (0.12-4.36 D). The percentage of corneal astigmatism of 1.0 diopters (D) or higher was 32.9% (457 eyes), of which 243 eyes (53.2%) were against-the-rule (ATR) astigmatism. With aging, the amount of ATR astigmatism was increasing. Axial length was not correlated with the amount of astigmatism (r=0.179, P=0.203). Corneal astigmatism was mirror symmetry in both eyes of one person.

Astigmatism, especially mild astigmatism, was common in patients with cataract, which suggests the importance of astigmatism correction. The symmetry of astigmatism should be considered when both eyes need cataract surgery. Axial length is not related to astigmatism, indicating that the measurement and correction of astigmatism are important even in emmetropia eyes.