Visual dysfunction as the result of developmental disorders or acquired brain injury is a major source of disability in children. There are limited means to reliably measure visual dysfunction, or to treat visual dysfunction in children. At present, the only visual assessment procedure that has attained a Good Quality rating for Body-of-Evidence, and is Strongly Recommended for verbal children, is a modified Snellen chart using child-friendly, standardized ototypes. There is no methodology that meets these criteria for non-verbal children. For visual dysfunction, the only childhood visual disease that has a valid treatment protocol is amblyopia: Uncorrectable decrease in vision in one or both eyes due to altered visual experience early in life, affecting 2%-4% of the population. The only treatment for amblyopia that meets a Good Quality rating for Body-of-Evidence, and is Strongly Recommended is intermittent patching of the amblyopic eye before the age of 10. Promising assessment and treatment paradigms are in the pipeline for non-verbal children, and for brain injured children with cerebral visual impairment.