Prevalence and topographical characteristics of keratoconus as a type of corneal ectasia among adult Egyptians with refractive errors

Abstract

ObjectivesTo determine the prevalence of keratoconus (KC) among Egyptian adult population.BackgroundCorneal ectasia is a noninflammatory, bilateral, asymmetrical condition, causing progressive corneal steepening and thinning. KC is the most prevalent form of corneal ectasia and affects all ethnicities.Patients and methodsA cross-sectional study was conducted on 1607 adults at an Egyptian Governorate aged more than 18 years with high myopia of above − 6 D and high astigmatism above − 3 D old at some public and private ophthalmology centers, in Lower Egypt during the period from May 2020 till February 2021. Evaluation of corneal topography (Scheimpflug tomographer imaging system) and detection of any ectatic corneal conditions by corneal topography and analysis of their associated abnormal corneal parameters.ResultsThis study included 1607 patients, out of which 173 (10.8%) patients were diagnosed as having KC in one or both eyes. KC was more prevalent in right eyes (12.4%) than left ones (7.09%). The mean thickness of the thinnest corneal location (Mm) was significantly lower in the affected eyes (P < 0.001). K1, K2, Kmax, and anterior and posterior cornel maps were significantly increased among patients with KC4 than other different KC types. There was a significant negative correlation between KC grade and the thinnest location (r=−0.430, P < 0.001), and positive correlation between K1 (r = 0.274, P < 0.001), K2 (r = 0.391, P < 0.001), Kmax (r = 0.452, P < 0.001), anterior cornel map (r = 0.307, P < 0.001), and posterior cornel map (r = 0.306, P < 0.001) in eyes with KC.ConclusionThe KC is prevalent among Egyptian adults. Most cases had bilateral affection. Astigmatism was the most common refractive error being associated with KC with no statistically significant differences regarding sex or age.