Is myopia genetic or environmental? Also, at what age should kids wear contacts/glasses?

Myopia is thought to be caused by a combination of genetic and environmental factors. There is no minimum age for contacts and glasses. Every case is different so please refer to your child's pediatric ophthalmologist's recommendation if your kid does or does not need contacts/glasses. Source: http://www.aao.org/eye-health/ask-ophthalmologist-q/is-myopia-hereditary