Squint (strabismus) is a condition in which the eyes are not aligned properly and they point in different directions. Strabismus evolves due to a coordination deficiency in the extra ocular muscles, which results in the eyes being unable to gaze at the same point at the same time. Another reason for squint may be a brain dysfunction, which does not allow the eyes to coordinate correctly. In some cases, a squint may impede binocular vision, making it harder for the individual to carry out depth perception.
According to the National Health Service (NHS) of the United Kingdom, strabismus affects 5% of children and official data show that the condition usually develops during the first 36 months.
The main types of squint (strabismus) are:
- Esotropia – the eye is turned inwards.
- Exotropia – the eye is turned outwards.
- Hypertropia – the eye is turned upwards.
- Hypotropia – the eye is turned downwards.
What Factors May Trigger Strabismus?
- Myopia, hypermetropia or astigmatism – any of these refractive errors make the child turn the eye inwards in an attempt to focus better.
- Hydrocephalus – when excessive cerebrospinal fluid has built up around the brain, it can cause squints.
- Measles and other viral infections can cause strabismus.
- Noonan syndrome and genetic conditions can also lead to squint.
Treatment for Strabismus
The earlier in life the squint is diagnosed, the most efficient the treatment will be. If left untreated, it can eventually develop into amblyopia or lazy eye, a condition in which the brain ignores the input from one of the eyes in order to avoid double vision.
If strabismus is suspected, the child must be referred to an ophthalmologist. A routine eye test and the Hirschberg test (Hirschberg corneal reflex test) is used to diagnose and assess the condition. In the Hirschberg test, the ophthalmologist shines a light over the eye and observes the light reflection in the corneas.
Among the treatment options for strabismus we find:
- A common treatment for squint is wearing a patch over the healthy eye to help the squinting one to develop properly.
- Glasses – when hypermetropia is found, glasses usually solve the squint.
- Botox (botulinum toxin injection) – injected into a muscle in the surface of the eye, when no other cause is identified.
- Surgery – performed only when all other treatments have been exhausted. Surgery can restore binocular vision and realign the muscles of the eyes.