Prevalence Of Keratoconus In Egyptian Subjects With High Corneal Astigmatism

Purpose: To determine the prevalence of keratoconus in subjects with corneal astigmatism of two diopters (2D) or greater using data from the Pentacam Scheimpflug images.
Methods: This prospective cross-sectional study included 1200 eyes of 1200 patients seeking refractive surgery who are older than 18 years and not previously diagnosed as keratoconus. Patients were divided into Group I (Patients with 2 diopters or greater of corneal astigmatism) and Group II (Patients with less than 2 corneal astigmatism).the second group was taken as a comparative group.
Results: The cornel cylindrical refractive error among individuals in-group I (high astigmatism) was -2.93 ± 0.89 ranging from -2.00 to -7.0. In-group II (low astigmatism) the cylindrical refractive error among normal individuals was -0.7 ± 0.49 ranging from 0.0 to –1.75. It was found that among group I population (high astigmatism) 12.3% diagnosed as keratoconus patients, while 1.7% of group II (low astigmatism) were keratoconus patients. There was a highly significant difference between the two groups (P < 0.00001).
Conclusions: The current study showed that subjects with 2D or more of astigmatism had higher prevalence of keratoconus than subjects with less than 2 D astigmatism