It is the condition where eyes cannot look in parallel. 

Eyes turning inward are mostly seen in children.

In diplopia, eyes may turn inward, outward, upward or downward.

Eyes turning inward detected within the first 6 months after the birth should be certainly treated until the infant is one year old.

Especially in eyes turning inward, amblyopia may develop.

The degree of amblyopia is not associated with the level of diplopia.

In a low degree of eye crossing, a serious loss of vision may occur.

Eyes turning outward may be seen at intervals in the early phase.

Such a crossing may become permanent over time. 

Eyes turning outward is more frequent together with myopia.

The diplopia surgery should be performed under general anaesthesia.

In the surgery, changes are made in the motor muscles situated on the eyeball in a function enhancing or reducing way.

Surgeries are not required in treatment of each type of diplopia; some patients can be treated with glasses.