“Squint (known as strabismus in medical terminology) is a condition where the two eyes do not work together as a pair and hence look in different directions.”
A person may be born with squint or develop one later. In the case of a squint, one eye looks forward to focus on an object, the other eye may turn inwards, outwards, upwards or downwards. Squints are common in children and may affect three to five per cent of all children, i.e. four in 100 children. It is usually seen before the child is four years old. Squints are less commonly seen in older children and adults. Squint may be constant and seen throughout the day or may be intermittent. It is very important to seek medical advice if you think your child has squint. If squint is diagnosed and corrected early, chances of visual recovery is good.
What causes a squint?
In most of the cases, the cause of squint is not known. Normally our eyes work together synchronously like the wipers of a car. If this synchrony is disturbed due to any reason, it leads to misalignment of the two eyes resulting in a squint.
- Some cases of refractive errors, commonly hypermetropia (long sightedness) can cause squint. Children with hypermetropia tend to over focus to see things clearly. This over focusing tends to turn the eye inwards, causing squint. It is usually noticed when a baby is looking closely at a toy or when a child is concentrating on a close object or reading.
- Squint may develop if there is poor vision in one eye due to cataract, retinal disease, optic nerve disease, eye tumors, injuries etc.
- Sometimes a baby is born with a squint. In such cases there may be a family history of squint and it has a genetic element.
- Children with neurodevelopmental delay motor control problems, and premature children have a higher risk of developing squint.
How do I know my child has squint?
Usually squint is noticed by parents, relatives, and friends or by your doctor. You may notice that your child is not looking straight. Your child may complain of blurred vision or double vision. Your child may tilt his head or chin to see well or to avoid double vision. When in doubt regarding your child’s squint, taking photographs with flash can help identify the squint, especially in children who refuse to cooperate while examining
What are the consequences, if squint is not treated?
If your child’s squint is not corrected, you child has the risk of developing a lazy eye, also called amblyopia. In a child with squint, because the two eyes are focusing differently, two different images are sent to the brain. The brain learns to suppress the image of the squinting eye (as it is not clear). The squinting eye becomes a lazy eye where the vision fails to develop in that eye due to its non-use.
Lazy eye should be treated before seven years of age. If squints are not corrected, your child will fail to develop binocular single vision or BSV. BSV is the ability of the brain to fuse the two images received from the two eyes to give a three dimensional view. BSV develops during childhood and helps us to see the world in three dimension and to interpret depth i.e. the ability to judge the distance between two objects. If the squint is not corrected, BSV fails to develop and the vision is affected. Motor skills requiring manual dexterity, speed and accuracy may be affected in children who develop a lazy eye. Squint can also cause cosmetic problems. The child can develop low self-esteem and confidence.
How is squint corrected?
The aim of treating squint is to restore vision, straighten the eyes and restore BSV. The eyes should ultimately work normally and look normal.
- Spectacles: Vision should be corrected with glasses if there is refractive error. Glasses not only improve the vision but will also help to keep the eyes straight.
- Occlusion/patching: If the child has developed a lazy eye, patching would be considered. In patching, the good eye is covered so that the affected eye is forced to see. Parent’s cooperation and regular monitoring is very important for the success of this treatment.
- Orthoptic exercise: Sometimes simple exercises, which encourage the eyes to work together, are advised.
- Surgery is done to straighten the eyes and align them properly. Surgery is usually done when the squint is pronounced and not improving with glasses. There are different types of surgery and the choice of surgery will depend on the cause and severity of the squint. Surgery cannot replace glasses and your child may need to wear glasses even after surgery.
- Botulin A: If the squint is due to an eye muscle problem, Botulin A toxin may be injected into the muscle. It is a temporary measure and may need to be repeated.
Can adults develop squint?
Sometimes squint that has been corrected in childhood can reappear in adult life. Squints that develop in adult life will result in double vision. They need to be investigated and treated.
What are the long-term outcomes of squint?
Most children with squint who are treated early achieve good vision. If squint is not corrected by seven years of age it can permanently affect the vision that cannot be corrected in adult life. Your encouragement and support as a parent is very important for the management of 80 squint.