The Eustachian tube connects the throat and the middle ear (the site of a typical  ear infection ) and allows air to travel between them and equalize the pressures. When the Eustachian tube is temporarily pinched off, pressure can build up in the middle ear.
Visitation is a matter of state law, but generally speaking, every state allows parents to exercise a reasonable amount of visitation with their children, which generally means enough time to establish and maintain a meaningful relationship.
A court may award visitation rights if the child's parents have filed for divorce, one parent is deceased and the other parent has unreasonably denied visitation to the grandparent, or when a parent or parents unreasonably deny visitation to a grandparent for more than 90 days.