How do you know if you have bad eye sight if a child?

Doctor can determine: Children should have an eye exam at 6 months, 3 years and 5 years at a minimum. At these ages, doctors can detect problems and intervene before they result in permanent deficits.

Evaluate if suspect: Any newborn should see clearly at least a foot & mom's can usually tell when they fix their gaze & smile.Later good equal vision in both eyes helps them fix the alignment of their eyes in the same direction.By the time they crawl,pull up,walk they should see a raison on the floor and pick it up.There doc should be assessing this at well checks.Eye docs can verify vision with special tools.