Squint


 

What is squint?
It is the common name for “strabismus” where the eyes are not aligned in the same direction. The squinting eye may turn in (converge), turn out (diverge) or sometimes turn up or down. These can be present all or only part of the time, in one or alternating between two eyes.  

 

What causes squint?
It can arise due to an incorrect balance of the muscles that move the eye , refractive error, childhood illnesses , nerve palsy etc.


Preop- left eye divergent and up

Postop-straight gaze
Is it only a cosmetic problem?
Not always .It can be associated with decreased vision or diplopia (double vision). Loss of binocular vision (ability to use the eyes together) can lead to loss of fine stereopsis (depth perception) and peripheral visual field.

Preop-left eye convergent

Postop-straight eyes


Postop-straight eyes

Preop- divergent squint


Left eye divergent squint before surgery

Left eye straight after surgery


Accomadative squint corrected with spectacles

Squint eso accomadative


Accomadative squint esotropia

Squint accomadative corrected with glasses


Intermittent divergent squint

IDS corrected after surgery




 

How is squint assessed ?
It is assessed by various orthoptics test, the aim of which is to

  • Establish the amount and type of squint
  • Assess how well can the child /adult see = refraction
  • Test for binocular vision
  • Fundus examination including fixation pattern
  • Investigate for the cause of squint

What are treatment options?
Strabismus can be treated in various ways. Depending on the individual case, treatment options include:

  • Glasses
  • Prisms in spectacles
  • Patching of eye
  • Botox injection
  • Surgery
Childhood Squint:
Squint can present at any age. The cause is not always known, but if squint is suspected, then the baby should be seen for accurate assessment at the earliest opportunity. Sometimes a “pseudosquint” may be present due to wide gap between the eyes , flat nose bridge etc where the eyes appear to be misaligned but do not actually have squint.

What are the causes of childhood squint?

  • Congenital squint-these children are born with a squint , though it may not be obvious for few weeks. A strong family history could be present . In all children the vision and need for spectacles has to be assessed.
  • Long sightedness or hypermetropia-as the child cannot focus well for near , he has to put extra effort to focus. T he over focussing produces double vision. To avoid this double vision, the image in one eye is suppressed unconsciously and in turn the child avoids using that eye. If left untreated not only does the eye deviates but also becomes a lazy eye (amblyopia)
  • Childhood illnesses:- Squint may also develop following viral fever, measles, meningitis etc
  • Injury:- to the nerves supplying eye muscles can lead to squint.
  • Hereditary
What is the treatment for childhood squint, will he need to wear spectacles or undergo surgery?
The child is thoroughly assessed to establish the type of squint. It is very important to note the vision and fixation pattern in both eyes. Treatment varies according to the type of squint and can be in the form of spectacles, occlusion, eyedrops (rarely) or surgery.
  • Some squints, especially those that arise from hypermetropia (long sightedness) respond well to treatment with wearing of spectacles. The child will be seen from time to time to note the change in spectacle power and degree of squint till he grows up. Any residual squint not corrected by spectacle can than be corrected by surgery.
  • Amblyopia/Lazy eye:- This is treated by patching /Occluding the good eye. The weaker eye is encouraged to work harder with visual activities such as colouring and reading while patch is on.
  • Surgery:- Sometimes this is the only choice to straighten the eye. If done at appropriate time results can be very good and 3 D vision can develop.
Adult Squint:
When an adult presents with squint it is not only imperative to establish the type and amount of squint but also to establish and treat the cause of squint if any. By and large, they are either non-paralytic or paralytic squint. The non-paralytic variety either persisted from childhood or is a local extra ocular muscular imbalance. Any adult presenting with acute (sudden) onset of paralytic squint has to be investigated in detail for the cause, which could be medical, e.g. hypertension, diabetes mellitus or surgical e.g. brain lesion. Majority of these kinds corrects on their own within 6 months and surgery is only required in cases where squint persists.
What happens in squint surgery?
There are six muscles attached to the outside of each eyeball, which move eye in various directions. During surgery some of these, often 2, are weakened or strengthened (by moving their attachment backward or forward) to make the eye straight. The procedure is done under local anesthesia in adults and general anesthesia in children. It is done as a day care procedure.

Will more than one surgery be required?
It is not uncommon for more than one operation to be necessary. This does not mean that something has gone wrong but that fine-tuning is needed to obtain the best straight alignment. Sometimes the squint is too large and hence 2-stage surgery is planned.

 

Won't straightening my eyes after all these years cause me to see double?
Double vision may occur after straightening eyes that have been out of alignment for many years. However, it is generally a transient problem, lasting only a few weeks until the brain adapts to the new eye position  



What happens after the operation?

It is a day care surgery with no hospitalization. The eye pad is removed the next day and eyedrops are instilled a couple of times during the next weeks. Since it is an external surgery there is no effect on the vision. Most of the times external sutures are absorbable and do not have to be removed. Though the eyes may be red initially a person can join back his office in couple of days.

 

Am I too old to have my eyes straightened?
Eyes can be straightened at any age. If you feel that it will enhance your quality of life, you may want to consider it

 


Right eye-convergent squint

Right eye-corrected straight after surgery
 


Inferior Oblique muscle transposition

Synaptophore-Squint-Orthoptic examination