All you need to know about squint eyes

What is squint (strabismus)?

Very simply put, squint is an eye condition wherein both the eyes point in different directions. While one eye focuses on a particular object, the other eye focuses away from it—either downwards or upwards. Sometimes it may even focus away and come back, and sometimes it keeps moving back & forth between the object and the surroundings. Such misalignment of the eyes is referred to as squint or strabismus.
Dr. Niteen Dedhia's talk on squint eyes
Squints are more common in children - approximately 1 in 20 children suffer from this. It usually develops before a child becomes 5 years of age, but can appear in adulthood as well. Note : It is not necessary that all squint patients experience misalignment throughout the day—many a times patients suffer from squint conditions for certain parts of the day and have normal eyesight for the remaining part of the day.

What causes squint?

The reason for squint may not always be apparent. Some children are born with squinted eyes (congenital squint) and some develop it later on (acquired squint). Acquired squint is caused when the eye tries to overcome certain vision problems like refractive errors, mainly, Congenital squint is caused due to,
  • Weakened eye muscles or abnormal eye nerve impulses to the eye, or
  • Hereditary causes
In rare cases, other causes that may also result in squinted eyes are
  • Childhood illnesses, for instance, viral infections such as measles
  • Certain genetic conditions such as Noonan's or Down's syndrome
  • Hydrocephalus, which is caused by a build-up of fluid in the brain
  • Other eye problems, such as abnormal development of the muscles that move the eye, a problem with the retina (the layer of light-sensitive nerve cells at the back of the eye)
  • Pathology inside the eye, such as cataract, corneal scars, glaucoma, tumours of the eye, etc.
  • Retinoblastoma, a rare kind of eye cancer
There are greater chances of being affected with squint if,
  • There is a family history of squints, lazy eye (amblyopia) or needing glasses
  • Having a condition that affects the nervous system, such as cerebral palsy
  • Being born early (prematurely) or with a low birth weight

Symptoms of squint

Know this : The eyes of new-borns are rarely aligned 3 to 4 weeks after birth. It is only after a month that you should be concerned if your child's eyes are still misaligned. In such scenarios, get him/her checked by an ophthalmologist instantly. The most obvious symptom of squint is the eyes looking in different directions. Apart from this, other symptoms include:
  • Instantly closing the squinted eye when exposed to bright sunlight
  • Faulty depth perception
  • Tilting the head in a certain direction when trying to focus on an object in order to use both eyes
  • Experiencing double vision or confusion
When left untreated for a long time, squints may result in lazy eye (amblyopia) — a condition where the brain begins to ignore signals coming from the eye with the squint.

How is squint diagnosed & treated?

Parents often believe that children will outgrow their squint condition, but this not true. As the child grows older, it becomes more difficult to treat squint and regain the lost vision. However, cosmetically straightening the eye is possible at any age. To diagnose squint and know its true cause, the ophthalmologist performs a battery of tests including,
  • Complete eye examination
  • Detailed study of the inner parts of the eye
  • Corneal light reflex
  • Cover/uncover test
  • Retinal exam
  • Visual acuity
A brain and nervous system (neurological) examination is also be performed. In some cases, there may be a false appearance of squint due to a broad nasal bridge in a child. An ophthalmologist will be able to differentiate between a true squint and false squint. Once the squint and its cause are confirmed, depending on the results, various treatments follow:
  • Prescribing glasses for children in the initial stages
  • Treating vision loss due to lazy eye if it is present
  • Surgery to correct the appearance of squint or restoring binocular vision

Surgical Treatment

Surgery is done under general anaesthesia in children and under local anaesthesia in adults, with their consent. To undergo general anaesthesia the child should be free from acute illness. The ophthalmic surgeon should be informed if the child suffers from epilepsy or cardiac arrest. A blood test and an X-ray of the chest are conducted as part of routine examinations. Surgery is then performed on both eyes together or on one at a time depending on the severity of the squint. During the surgery, it is the eye muscles that are operated on. The eyeball is never opened. Post the surgery, the eye is bandaged for a day and eye drops may be prescribed for a month. Under cases of lazy eye, frequent follow-ups might be required, though normal activities can be resumed. Surgery cannot replace the need for glasses. If the child has significant refractive error, glasses are a must. In certain cases, a patching therapy might also be followed to maintain clarity of vision.