Food, supplements and myths

The short version

There is a floor: a child who eats ordinary varied food gets everything their eyes need, and no supplement lifts a well-fed child above it. Carrots do not sharpen sight; a severe vitamin A deficiency harms it, and that is a different problem in a different place. Eye exercises are real medicine for exactly one diagnosis (convergence insufficiency) and do nothing for myopia. Blue-light glasses have no good evidence for children's eyes. Vision-training packages, pinhole glasses and 'weaker prescription' advice range from useless to harmful. This topic says what not to spend money on and why, with the studies behind each answer.