Experts convened by the National Institutes of Health (NIH) have identified five elements of a brain-based condition that has emerged as a leading cause of vision impairment starting in childhood in the United States and other industrialized nations. Known as cerebral (or cortical) visual impairment (CVI), some estimates suggest that at least 3% of primary school children exhibit CVI-related visual problems, which vary, but may include difficulty visually searching for an object or person or understanding a scene involving complex motion. Their report, based on evidence and expert opinion, was published today in Ophthalmology.