Prevalence of Preoperative Corneal Astigmatism in Patients Undergoing Cataract Surgery at Mettapracharak Hospital, Thailand.

OBJECTIVE To describe and analyze the demography and distribution of preoperative corneal astigmatism in patients undergoing cataract surgery at Mettapracharak Hospital. MATERIAL AND METHOD The medical records of consecutive patients who had cataract surgery between October 1, 2010 and September 30, 2011 at Mettapracharak Hospital were retrospectively reviewed and analyzed. Patient demographic and keratometric data were collected and analyzed. RESULTS The present study evaluated the keratometric data in 2,688 eyes of 2,671 patients who had cataract surgery with the mean age of 66.23±10.79 years. The mean corneal astigmatism was 1.09 D (range 0.00-8.50 D). Corneal astigmatism was higher than 1.00 D in 36.6%, between 0.51 D and 1.00 D in 37.9% and 0.50 D or less in 25.5% of eyes. The mean steep keratometry and flat keratometry values were 44.89±1.52 D and 43.81±1.57 D respectively. The magnitude of corneal astigmatism was positively correlated with age (p<0. 001) and there was a tendency for corneal astigmatism to increase with age above 50 years. Female had significantly steeper corneas than male. Corneal astigmatism was mainly against-the-rule (the steepest meridian at 180±30 degrees). The type of corneal astigmatism was strongly correlated with age. Against-the-rule astigmatism increased with older age. While aging decreased with-the-rule astigmatism. CONCLUSION The present report showed the pattern of corneal astigmatism before cataract surgery in Thai governmental hospital, approximately one third of cataract patients had more than 1.00 D of astigmatism. This finding provide the important normative reference and help ophthalmologists to plan and manage the cost-effective correction of preexisting corneal astigmatism in cataract patients to achieve the best visual outcome.