Squints in Children
What is an Eye Squint?
A squint (strabismus) is an eye condition in which the eyes do not look in the same direction. While one eye looks forwards and focuses on an object, the other eye turns inwards or outwards, upwards or downwards.
Squints are common, mainly in young children and affect around one in 20 children. Early detection is important to avoid the eye becoming lazy with poor sight.
At birth the eyes and brain do not work together very well. With growth the connection builds between them, and this visual pathway continues to develop until the age of about 8 years. Catching and correcting a squint as early as possible plays an important role in the loss of vision.
The Causes of Squint in Children
Very often it is difficult to attribute the cause of a squint. However listed below are some of the possible causes:
- Family history – where a parent has had a squint or needed glasses from an early age a child is at more risk of developing a squint
- Prematurity – a child born before 32 weeks of pregnancy is more likely to develop a squint.
- General health – children with conditions such as Down`s syndrome or cerebral palsy are prone to develop a squint
- Other eye conditions – any eye condition which affects the sight is likely to likely to cause a squint to develop.
Before the age of three months it can be difficult to detect the presence of a squint, and during the first few months it’s normal that the eyes may, on occasion, not work together, but if a parent suspects that a squint is present, the GP should be consulted.
It is particularly mothers (who more often feed the child) that are in a position to observe a squint.
More commonly a squint develops between the ages of eighteen months and four years.
Refractive Errors In Childhood
Refractive errors such as those listed below affect vision and may need corrective lenses for correction or improvement:
- Short Sightedness (myopia) is not a common cause of childhood squint because it usually develops after vision has developed and in any case near objects are seen clearly without the need for excessive focussing.
- Long Sightedness (hypermetropia) is a common cause of childhood squints because it is usually present at birth (most children are a little long sighted at birth and this becomes less as the eye grows). Both near and distant objects are blurred.
- Astigmatism (the front of the eye not being quite spherical or round) everything appears blurry. Blurry vision interferes with visual development and can cause amblyopia (poor sight), often referred to as a lazy eye.
Effects of A Squint on Vision
If a child develops a squint each eye will be looking in a different direction and therefore sending a different picture to the brain from each eye and as the eyes are not working together double vision will occur.
Because the visual system is still developing the brain can stop the double vision by ignoring the image coming from the eye with the squint. The sight in the squinting eye will not develop normally and will become ‘lazy’ with poor sight.
Children can easily adapt to using only one eye and are not aware that a problem exists. It is often only when an eye examination is conducted that the problem is discovered and this is an important reason for early testing of a child`s eyes, as early treatment is very effective.
Detection of Squints
It is government policy that all children are screened around the time they start school to ensure that there is no problem with visual development. The parent should ask at the child`s nursery or school if the vision has been checked, and if not request referral to an orthoptist. An orthoptist is an expert in how the eyes work together and is very skilled in testing vision in young children, diagnosing squints, prescribing patching and eye exercises.
Treatment of Squints
There are a number of treatments for squints:
- Glasses. These are appropriate when a refractive error is present.
- Occlusion therapy (patching). The good eye is patched to enable the pathway between the squinting eye and the brain to develop.
- Exercises. These may be necessary to help the eyes work together.
- Surgery. This is to weaken or `strengthen` the muscles of the eye so that the eyes are in better alignment, but does not improve the level of vision.
- Botulinum Toxin Injection (Botox). This serves to weaken a muscle and is only considered for certain types of squint.
Result of Treatment of Squints
When a squint has been detected early, and certainly before the age of eight years, the outcome both cosmetically and functionally can be very good.
Even when a child is left with poor vision in one eye there should be no day to day problem for the majority. The ability to drive is seldom a problem. Certain occupations such as the police and the forces, particularly pilots are required to have a certain level of vision in both eyes. An orthoptist can advise about the requirements for certain jobs.
- NHS Choices – Squint: http://www.nhs.uk/conditions/Squint/Pages/Introduction2.aspx
- Healthxchange, Childhood Squints Fact Sheet: http://www.healthxchange.com.sg/healthyliving/childrenhealth/Pages/Childhood-Squints-Fact-Sheet.aspx