Tomographic and Refractive Characteristics of Pediatric First-Degree Relatives of Keratoconus Patients

PURPOSE: To evaluate the tomographic and refractive characteristics of pediatric first-degree relatives of patients with keratoconus. DESIGN: Cross-sectional study. METHODS: SETTING: Department of Ophthalmology at the American University of Beirut Medical, Beirut, Lebanon. STUDY POPULATION: Pediatric first-degree relatives of patients with keratoconus. Both eyes of all participants aged between 6 and 18 years were included and studied. EXCLUSION CRITERIA: Soft contact lens use in the past 2 weeks or rigid gas-permeable lens wear within 4 weeks, history of prior ocular surgery or infectious keratitis, and unreliable corneal tomography. MASKING AND RANDOMIZATION: Two masked cornea and refractive surgeons of different training backgrounds independently evaluated the participants' tomographic outputs. Additionally, the tomographic data were analyzed using Smadja's decision tree. OBSERVATION PROCEDURES: Scheimpflug tomography, manifest refraction, and slitlamp examination. MAIN OUTCOME MEASURES: Anterior curvature indices, posterior elevation values, thinnest pachymetry, and subjective and objective tomographic interpretation. RESULTS: One hundred eighty-three subjects were recruited. Tomographic evaluation after Cohen's kappa coefficient analysis revealed 32 patients as having keratoconus (17.5%), while 35 patients (19.1%) were labeled as keratoconus by objective analysis. There were 11.5%-15.5% of patients with keratoconus aged less than 11 years, 18.0% aged 12.15 years, and 25.5% aged 16.18 years. Their respective steepest anterior curvature and thinnest pachymetry are 44.8 +/- 6.5 diopters (D) and 515.9 +/- 39.2 mu m, 47.34 +/- 3.4 D and 496.1 +/- 37.9 mu m, and 49.7 +/- 6.1 D and 486.0 +/- 66.5 mu m. A total of 37.5% of the keratoconus patients were unilateral as evaluated by tomography alone. CONCLUSIONS: The prevalence of keratoconus in pediatric first-degree relatives of diagnosed keratoconus patients is high. Screening in this high-risk group is warranted. (C) 2019 Elsevier Inc. All rights reserved.