Squint or Strabismus/ Crossed Eye is a visual problem in which the eyes are not aligned properly and point in different directions. One eye may look straight ahead, while the other eye turns inward, outward, upward, or downward. The eye turn may be constant or may be seen at certain times only i.e. intermittent. Squint can affect both children and adults.
Amblyopia (lazy eye) is the decrease of vision in one or both eyes due to abnormal vision development during childhood, results in blurry vision. It can be caused by the presence of crossed eyes (strabismus), unequal farsightedness or nearsightedness (refractive error), or a physical obstruction of vision like cataracts. It is one of the leading causes of vision loss in children.
Here we explore some of the concerns faced by parents whose children have a squint or lazy eye:-
Why does my child squint?
The exact cause of squint is not known.
Six muscles control the movement of each eye. Each of these muscle acts along with its counterpart in the other eye to keep both the eyes aligned properly. A loss of coordination between the muscles of the two eyes leads to misalignment.
Squint may also be caused by poor vision or a sight-threatening condition in one eye. Therefore it is important in all the cases of squint, especially in children, to have a thorough eye checkup to rule out any other cause of loss of vision for e.g cataract, corneal opacities, high refractive errors and rarely eye tumours like retinoblastoma etc. Sometimes paralysis of one eye muscle can result in a squint.
Is squint common in children?
Squint is fairly common in children; it is estimated that almost 3% of children have a squint.
What are the problems faced by a patient with a squint?
In children, squint can cause loss of depth perception (3D vision) and lazy Eye (poor development of vision in the squinting eye)
An adult cannot ignore the image from either eye and therefore they can complain of double vision.
What is depth perception/ 3D vision?
When both the eyes have good vision and they are aligned properly, they focus on the same object. Each of the eyes sends a picture of the same object, viewed from a slightly different angle. These two images reach the brain, where they are fused to form a single three-dimensional picture with depth perception. This gets affected in children with a squint.
How is squint diagnosed?
The squint is diagnosed by the ophthalmologist specializing in that field. He or she would do a few special tests to confirm the presence of squint and find out the type of squint. In some cases, there may be a false appearance of squint due to the broad nasal bridge in a child. This is called as pseudo squint.
When should the squint be treated?
In a child, the treatment of squint and any associated amblyopia should be started as soon as possible. Remember that the child would never outgrow the squint. A delay in treatment may decrease the chances of getting a good alignment and restoring vision.
Earlier treatment equates better results!!
What are the treatment options?
Treatment depends on the type and constancy of squint and age of presentation. It normally includes one or more of the following:
- Patching therapy/ Occlusion therapy
FAQs – Squint (Strabismus)
Are glasses necessary?
If the child has a significant refractive error, glasses are a must. In some cases like inward squints or esotropia, wearing glasses may correct the squint. In other cases, wearing glasses help the eyes to see clearly. This clear vision is very important for the treatment of amblyopia, and also for maintaining the alignment of eyes after they have been aligned by surgery.
Remember surgery cannot replace the need for glasses.
What is patching / Occlusion therapy?
In some children, squint or high refractive errors cause the eye to become ‘lazy’ and consequently the vision to be blurred in the eye despite using glasses. Patching the ‘good’ eye will make the lazy eye work harder, which improves vision.
Occlusion therapy improves vision it does not treat the squint. The schedule and duration of therapy are tailor made to the age of the child, the density of amblyopia and the response to therapy. It is thought that the patching therapy works best for children below 7-8 years of age.
How does one decide about squint surgery?
Treatment of squint generally requires eye muscle surgery. However, some patients may need glasses, prisms, or may be best left untreated. The best way to determine whether straightening of the eyes is possible and appropriate is to undergo an examination by a strabismus surgeon who is experienced in treating squints. Constant squints in children should ideally be corrected before the age of 2 years to prevent amblyopia.
Is adult squint surgery only cosmetic?
Advances in the management of misaligned eyes now provide benefits to most adults as well as children. Treating adults with strabismus can improve the way the two eyes work together, and the field of vision. Many patients report improved self-esteem, communication skills, and job opportunities additionally.
What are the success rates of a squint surgery?
Nearly 80-90% patients are successfully corrected in the straight-ahead position with one surgery. In some patients, the surgery may be only partially successful. In some patients the eye alignment will change over time, resulting in the need for additional surgery after few months or years.