A squint, or strabismus, is a condition in which the eyes do not align properly.
One eye turns inwards, upwards, downwards, or outwards, while the other
one focuses at one spot.
It can happen all the time or intermittently.
This usually occurs because the muscles that control the movement of the eye
and the eyelid, the extraocular muscles, are not working together.
As a result, both eyes are unable to look at the same spot at the same time.
It can also happen because a disorder in the brain means that the eyes cannot
correctly coordinate.
Strabismus also makes binocular vision impossible, so it is harder for the person to appreciate depth perception.
The following terms describe strabismus by the positions of the eye:
The sign of a squint is fairly obvious from an early age. One of the eyes does not look straight ahead. A minor squint may be less noticeable. Infants and newborns may go cross-eyed, especially if they are tired. This does not mean that they have a squint. Parents can check with their doctor. If a child has one eye closed, or turns their head when looking at you, this could be a sign of double vision, and a possible squint. It is a good idea to see a doctor. Strabismus is normally either present at birth or it develops in the first 6 months after birth.
[Double vision] Strabismus can lead to double vision if it returns in adulthood. Untreated, it can lead to amblyopia, or 'lazy eye', in which the brain starts ignoring input from one of the eyes. The brain ignores one of the eyes to avoid double vision. If there is poor vision in the affected eye, a child may benefit from wearing a patch over the other eye to encourage the vision to develop.
Sometimes a squint that was treated successfully in childhood returns later in adulthood. This may lead to double vision in the adult because, by that time, the brain has been trained to gather data from both eyes, so it cannot ignore one of them.
Causes
Strabismus can be:Treatment options include: