A study investigating the corneal power and degree of astigmatism in 520 patients at a university optometry clinic in Benin-City, Nigeria was undertaken. The mean low corneal power and the mean high corneal power were 42.7 +/- 1.5 diopters and 43.3 +/- 1.5 diopters, respectively. The mean corneal astigmatism was 0.61 +/- 0.63 diopters. Although female corneas were significantly steeper than those of males, there was no significant difference between the corneal astigmatism with regard to sex. The data reported suggest that nutrition plays a less important role in corneal astigmatism than other authors have proposed.