The so-called “crossed eyes”, also known as internal strabismus, occur in children, but can also occur in adults for some pathological reasons. Depending on the degree and nature of the strabismus, the treatment varies. In the case of children with internal strabismus, many parents will find that the child’s eyes are clearly congregated shortly after birth, and that there is a clear opposite eye appearance. This is called “pseudo-inclination” and does not require treatment. However, if there is an obvious eye position strabismus, the treatment should be decided according to the nature of the strabismus, as most children have hyperopia, and some of the adjustable strabismus can be corrected by wearing glasses with adequate correction and corresponding eye position training. However, if the strabismus is constant or partially adjusted, surgery is required in advance of glasses. In the case of pseudostrabismus caused by a flat nasal bridge, plastic surgery can be performed to improve the condition for cosmetic reasons, while other conditions are treated in a similar manner. However, most adult strabismus is a permanent strabismus, for which surgery is often the first option.