Jan RL, Weng SF, Wang JJ, et al. - Researchers conducted this nationwide, population-based, retrospective, matched cohort study to examine the risk of corneal ulcer in patients with atopic keratoconjunctivitis (AKC). The sample consisted of 171,019 newly diagnosed AKC patients who were identified by the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM), code 372.05, and selected from the Taiwan National Health Insurance Research Database. The age-, sex- and potential comorbidities-matched control group involved 171,019 patients with non-AKC chosen from the Taiwan Longitudinal Health Insurance Database 2000. In total, during the follow-up period, 2,018 patients with AKC and 1,481 controls developed a corneal ulcer. In patients with AKC, the incidence rate of the corneal ulcer was 1.42 times higher than in controls. AKC patients were 1.26 times more likely than controls to develop a corneal ulcer after adjusting for potential confounders, including diabetes mellitus, chronic renal disease, topical steroid ophthalmic agent use, lid margin disease, keratoconjunctivitis sicca, ocular blunt trauma and postcorneal transplantation. There was an increased risk of developing a corneal ulcer in patients with AKC and this risk should be advised.