Powierza K, Sawicka-Powierza J, Urban B, et al. - Researchers performed this cross-sectional study to determine endothelin-1 (ET-1) concentration in chronic idiopathic uveitis in children and adolescents depending on anatomical location and grade of inflammation. The sample consisted of 17 patients with chronic idiopathic uveitis and 22 healthy controls. In patients with chronic idiopathic uveitis and controls, a statistically significant difference between ET-1 concentration was found 1.33. ET-1 concentration and age were not associated, either in patients with chronic idiopathic uveitis or in controls. No variations were observed in ET-1 concentration between anterior, posterior and panuveitis, and in terms of grade of inflammation. In pediatric chronic idiopathic uveitis, ET-1 expression is disturbed regardless of the anatomical location and grade of inflammation. In disturbed vascular tone control, lower expression of ET-1 plays a crucial role and can result in permanent visual impairment in chronic non-infectious uveitis.