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Patient Corner

Childhood eye disease

Strabismus (Squint)

What is it?

Misalignment of the two eyes, so that both eyes are not looking in the same direction, denotes the term strabismus (squint). This misalignment can either be constant throughout the day, or may only be noticed at certain times during the day. It may also be that one (or both) eye(s) are deviated inward (eso deviation), outwards (exo deviation), upwards (hyper deviation), downwards (hypo deviation) or a combination of these.

This is a common condition in children, but can also occur in adults of any age. It always requires a comprehensive examination by the eye care professional, and may include special tests and interventions.


What are the causes of strabismus (squint)?

The exact cause is mostly unknown, but the mechanism seems to be when any of the 6 muscles in each eye (that co-ordinates eye movements), fail to act synchronously with each other, so that a misalignment occurs. It can be present from birth which may indicate a congenital strabismus, but may also occur later in life. It can be caused by a refractive error, organic pathology in one or both eyes, after trauma and also due to an intracranial pathology, where a disease process affects the nerves supplying these muscles.


What are the problems with strabismus (squint)?

When both eyes are not aligned to look in the same direction, they cannot focus on the same object simultaneously, and therefore sends different messages to the brain of the object in question. The effect can either be double vision (mostly in adults) or poor depth perception with underdevelopment of one eye or amblyopia (mostly in children).

If these problems are not addressed early, especially in children, underdevelopment of one eye can cause permanent loss of vision in that eye, and it is therefore necessary that all children with a squint be examined early and followed up regularly. In adults, any squint that causes double vision should also be investigated for intracranial pathology that can be treated.

 
How and when is strabismus (squint) diagnosed?

It is important to realise that the eyes of a newborn are rarely aligned at birth, and that only at about 3-4 weeks after birth alignment is fully established. Therefore any child older than one month with any misalignment of the eyes should be taken seriously and examination by an eye care professional should strongly be considered.

After a squint has been diagnosed by an ophthalmologist, some special tests will be carried out in order to determine:

  • The visual acuity (potential acuity) of the patient
  • Whether there is a true (or false) squint
  • The type of squint
  • The amount of deviation
  • Whether there is any refractive component that can be treated with glasses

  

What are the treatment options for strabismus (squint)?

Treatment for strabismus is never a short and easy solution to the problem. It requires long term follow-up and dedication from the patient (and the parent) alike.

It may involve conservative / temporary measures, and also surgical correction.

It is very important to note that the main aims of strabismus treatment in order of importance are:

  1. Preserving the vision
  2. Straightening the eyes
  3. Restoring binocular vision

If there is a refractive component to the squint, this can usually be corrected with spectacles. The ophthalmologist in conjunction with an optometrist will be able to prescribe spectacles that should be worn by the child for most of the day. After 3-6 months the child would then have to be re-evaluated to assess if the spectacles had any influence on the deviation / vision.

If amblyopia is present, this will need to be treated by either patching the stronger eye, or inserting a drop that dilates the stronger eye, so that the weaker eye can be “trained” to see again. This is one of the most crucial steps in the treatment of strabismus.

Surgical treatment is reserved for patients where conservative measures have failed to align both eyes, and in cases where the squint has been stable for some time. Surgery involves re positioning of some of the muscles that are attached to the eye.  It can involve one or both eyes, and may need to be repeated after the initial surgery in order to get good alignment.

After the surgery any refractive error or amblyopia must continue to be treated and follow up is crucial for the next months to years.

 

Please feel free to contact my office or to schedule an appointment if you suspect your child or someone you know to have strabismus (squint).