Squint is the common name for ‘strabismus’ which is the medical term used to describe eyes that are not pointing in the same direction. A squint can be convergent (esotropia), divergent (exotropia) or vertical.
The squint may be present all or only part of the time, in only one eye or alternating between the two eyes.
It has been estimated that four in every 100 adults suffer from this condition. Adult squints are of three main types: non-paralytic, paralytic and restrictive. Non-paralytic squints are usually a longstanding from childhood. The most common pattern is that an eye that was straight after childhood squint surgery later drifts out and causes concern over its appearance. In a paralytic squint an eye does not move normally because one or more eye muscles are weak or paralysed. This problem may have developed as a result of other health problems, such as damage to cranial nerves, following head injury or as a complication of diabetes or stroke. Such people will, most likely, suffer from troublesome double vision. Investigations may be required to discover the underlying cause. In a restrictive squint one or both eye do not move fully because of scarring or tethering of one or more muscles. A common example of this occurs in thyroid eye disease.