Keratoconus Frequency and Associated Risk Factors Among Patients Younger Than 18 Years With Significant Refractive Errors

Abstract

Introduction: Keratoconus is an ectatic corneal disorder that causes low vision secondary to high myopia, irregular astigmatism, and loss of corneal transparency. In children, the disease behaves aggressively, progresses rapidly, is diagnosed at advanced stages, and presents an increased risk for corneal transplantation; however, only few studies in children have been conducted. Purpose: The aims of this study were to determine the frequency of keratoconus in patients younger than 18 years who underwent the Pentacam study because of high myopia or high astigmatism in the oblique axis, analyze topographic criteria and classify them into severity groups, and identify associated risk factors. Methods: This was a retrospective observational cross-sectional study in which Pentacam examinations were analyzed. Frequency of keratoconus was determined and patients were classified according to visual acuity and severity scales. Medical records were reviewed to identify associated risk factors. Results: Four hundred twenty-six patients younger than 18 years were included, 40 (9.4%) had keratoconus according to Pentacam criteria. The mean age at diagnosis was 14.9 years, with male predilection (75%). Atopy was the only statistically significant risk factor, present in 85%. Family history was present in 7.5%. There were no differences in the distribution in groups according to visual acuity or Amsler–Krumeich scale. Most frequent ABCD classification was A2 (35.6%), B4 (47.9%), and C0 (35.6%), posterior curvature radius being a significant severity criterion. Conclusions: The study found that frequency of keratoconus in children is higher than previously reported. Atopy has a clear and possible causal association. Early detection should be sought to reduce the risk of progression. Pentacam is a fundamental tool for early diagnosis using simple criteria.