Health
By Dr Neeraj Jain, MD, DNB, MNAMS
(Consultant Ophthalmologist)
What is squint?
Squint or strabismus is the term used when the eyes are not pointing in the same direction. Squint which is also known as ‘turned eye’ or ‘crossed eye’ or ‘cock eye’ is due to lack of coordination of the 6 muscles of each eye that control the eye movements. Due to squint, the two eyes do not focus on the same object: one will focus on the intended object but the other looks somewhere else. If the eyes are not looking in the same direction, then they are sending different signals to the brain and this can cause double vision.
Most commonly one eye either turns in (esotropia) or out (exotropia). Occasionally one eye may be higher than the other (hypertropia). Besides the change in the direction, there may be other associated changes in the eyeballs, lids and eye structure in the cases of complex squint.
eyes with exotropia (turned out).
Eyes with esotropia (turned in)
Why do squints happen?
A squint can occur because of a number of different reasons which include
• damage to the muscles controlling the eye;
• damage to the nerves controlling the muscles;
• poor development or damage to the eye muscle control centres in the brain;
• poor visual development in the eye due to any eye disease can stop the brain from being
able to keep the eyes together.
Some of the reasons are present since birth, and some may be acquired later in life. So a squint can be seen at any age, from a few weeks after birth to old age.
Squint in Children
Strabismus is present in about 4% of children. There are many presentations of squint in children.
• Latent squint is one that only appears under stressful conditions such as fatigue.
• Transient squint is one that is noticeable for short periods and then seems normal.
• Alternating squint is one that changes between the eyes so the child can use either eye to fix vision.
• Constant or true squint is one that is permanent – always present.
The 2 serious squints are the constant and alternating ones, which require early referral. Early treatment is very essential as childhood squint interferes with normal visual development. The treatment should be started as early as possible.
What should I do if I notice a squint in my child?
If you notice that your child has some abnormal head posture or cock eye, please do not ignore this. Any suspected squint may be the reason for some underlying serious eye condition. It’s not always the case, but sometimes eye cancers do present as squint in the beginning. So a detailed eye examination is the first step. After a detailed eye examination, a plan can be charted out for squint correction and the visual rehabilitation of the child. It is always important to undergo rigorous visual rehabilitation after the surgery to maintain the normal position of the eyes.
If a true squint is not corrected before the age of 8, there is a danger that the ‘lazy eye’ will gradually lose vision from lack of use. This condition is called amblyopia. The golden rule is that a persistent squint needs early referral and correction. If treated early, the prospects for complete cure are good. Treatment commenced after the age of 8 is usually too late to save vision in the lazy eye. It becomes a permanently low vision eye.
To restore normal visual development, it is essential to correct it surgically or by other means. Adulthood squints are mainly corrected for cosmetic reasons. A large squint can be a cosmetic problem in a child or adult.
Childhood squint generally does not cause double vision, but squint acquired at later ages causes significant diplopia or double vision. The double vision can be very disabling and may need surgery for rehabilitation.
Can squints be treated?
A full assessment of your eye and vision is performed and the cause of the squint is assessed.
• The first step is to perform refraction and a detailed eye examination to establish the reason for and type of the squint.
• Some types of squints which are intermittent in nature can be helped by eye exercises.
• Surgical correction is done in most of the cases which are stable.
Please note that the myth, ‘a squint will usually correct itself’ is untrue.
• True or alternating squints need referral and correction.
• The ‘lazy eye’ will lose vision over time if not corrected by 7 years of age.
• Early surgical correction of a true squint, preferably at 1-2 years, is best.
