Objective: To estimate the prevalence and types of pre-existing regular corneal astigmatism in ageing population of Thailand on a community basis.

Materials and Methods: Data from the study of the “Epidemiology of Age-Related Macular Degeneration among the Elderly Population in Thailand”, a cross-sectional observational study done between December 11, 2009 and October 22, 2010, was retrieved by criteria with the age of 50 years or older. The participants who had either eye with aphakic, pseudophakic, or unknown lens status or ocular residual astigmatism (ORA) higher than 5.5 diopters were excluded. The refractive and corneal astigmatic parameters were used to calculate the magnitude and axis of corneal astigmatism and ORA following Alpins method.

Results: There were 3,130 of 10,250 eyes (30.5%) with corneal astigmatism higher than 1 diopter. The pattern of magnitude and proportion of against-the-rule (ATR) corneal astigmatism has been increased by every decade of age. The mean magnitude of corneal astigmatism in the northeastern area was -0.80±0.75 diopters, which was the highest and significantly different from that of the other areas except the central area (p<0.05 by Scheffe’s test). The mean magnitude of ORA of the central area was the lowest and significantly different from that of the other areas except the capital part (p<0.05 by Scheffe’s test).

Conclusion: The prevalence of corneal astigmatism in the present community-based study was 30.5%, which was slightly lower than the previous hospital-based reports. The tendency of increasing magnitude and ATR proportion of corneal astigmatism with ageing was comparable to previous studies.

Keywords: Corneal astigmatism, Thai elderly, Community based

Received 15 Mar 2019 | Revised 21 Oct 2019 | Accepted 28 Oct 2019