Clinical: The basics - Strabismus.

Strabismus can affect a patient's quality of life including interaction with peers.

In order for the eyes to move fully and together, there has to be correct functioning of the extraocular muscles, cranial nerves III, IV and VI, and the higher cortical centres, which control the speed of eye movements.

Problems in the function of any of these can lead to the development of strabismus or a squint.

Strabismus describes the appearance of the eyes when the visual axis fails to meet at the fixation point. A squint can be convergent or divergent.

1. Congenital squint

Congenital squints occur in those under six months old.

Although squints are common in neonates, the eyes should be fully aligned by around three months of age.

2. Non-paralytic squint

A non-paralytic or concomitant squint is when the squint occurs in all directions of gaze. Double vision does not usually occur. The eye that does not fixate usually has amblyopia. A non-paralytic …