A squint is a condition where the eyes point in different directions. One eye may turn inwards, outwards, upwards or downwards while the other eye looks forward. The medical name for a squint is strabismus.
Squints can also cause:
• Blurred vision
• Double vision
• Lazy eye (amblyopia) – when the brain starts to ignore signals coming from the eye with the squint.
Symptoms:
• The most obvious sign of a squint is eyes that look in different directions.
• Most often, one eye turns inwards (convergent squint) or outwards (divergent squint).
• In rarer cases, it may turn up or down (vertical squint). They can either be apparent at all times (constant), or only be apparent at certain times (intermittent).
• Minor squints are not always obvious.
• Squints can also cause blurred vision or double vision, but babies and young children may not realize there is a problem.
Causes:
The exact cause of a squint is not always known. Following are some causes of sqiunts:
1. Congenital Squints:
In most cases, babies are born with a squint or develop one because of a problem with their vision. If a baby is born with the condition, it is called a congenital squint. Squints that develop later are called acquired squints.
2. Refractive Error:
Acquired squints are sometimes caused by the eye's inability to focus light that passes through the lens. This is known as a refractive error. Types of refractive errors include:
• Short-sightedness (myopia) – a sight problem that affects your ability to see distant objects.
• Long-sightedness (hyperopia) – a sight problem that affects your ability to see close-up objects.
• Astigmatism – where the cornea at the front of the eye is unevenly curved, which causes blurred vision.
If a child has a refractive error, their eye may turn inwards or outwards as it attempts to focus. Squints caused by refractive errors usually develop in children aged two years or older. They tend to be most common in children who are long-sighted.
Other causes:
Although most squints are congenital or caused by refractive errors, in rare cases they are the result of:
• Childhood illnesses, for example viral infections such as measles, although it is possible these illnesses simply accelerate a squint that would have developed anyway.
• Some genetic conditions, such as Down's syndrome.
• Hydrocephalus, which is caused by a build-up of fluid in the brain.
• Other eye problems, such as abnormal development of the muscles that move the eye, or a problem with the retina (the layer of light-sensitive nerve cells at the back of the eye).
Increased risk:
Some things may increase the risk of a child having a squint, including:
• Having a family history of squints, lazy eye (amblyopia) or needing glasses.
• Having a condition that affects the nervous system, such as cerebral palsy.
• Being born early (prematurely) or with a low birth weight.
Treatment:
It is important that a squint is treated as soon as possible after being detected. If it is not treated, vision problems, such as those caused by a lazy eye (amblyopia), are likely to get worse or could become permanent. Treatment is most effective in very young children. Several types of treatment are available for squints, including:
• Glasses
• Eye exercises
• Botulinum toxin injections
• Corrective surgery
