Strabismus is defined as a misalignment of the eyes.
Strabismus also called as squint.
Orthophoria – Implies as perfect ocular alignment
without efforts.
Strabismus consists of two subgroups. 1.Hetrotropia – this is a manifest squint.
Esotropia – deviation of eye towards inside.
Exotropia -- deviation of eye towards towards
outside.
Hypertropia-- deviation of eye towards
upside. 2.Hetrophoria—this is a latent ocular
deviation. Eye alignment is maintained with fusional
effort.
Esophoria – inward deviation of eye when fusion is
disrupted.
Exophoria-- outward deviation of eye when fusion is
disrupted.
Hyperphoria-- upward deviation of eye when fusion is
disrupted.
Incyclophoria-- Intortional movement of eye when
fusion is disrupted.
Excyclophoria-- Extortional movement of eye when
fusion is disrupted.
Infantile Esotropia
Clinical features:
1.Onset between birth and six months of age.
2. Large size (greater than 30 dioptres).
3. Stable size.
4. Either alternation or fixation preference
may be present
5. Neurologically normal
6 The patient may or may not have any or all
of the following associated conditions:
Oblique muscle dysfunction, vertical
incomitance, dissociated vertical deviation,
asymmetric optokinetic nystagmus,
torticollis. The patient may or may not have
any or all of the following associated
conditions: Oblique muscle dysfunction,
vertical incomitance, dissociated vertical
deviation, asymmetric optokinetic nystagmus,
torticollis.
8. Initial alternation of the squint present
with crossed fixation - i.e. the affected
individual uses the left eye to look right
and the right eye to look left.
9. Limited potential for binocular vision.
Differential Diagnosis
1. Sixth cranial nerve palsy
2. Primary Constant esotropia.
3. Duane's Syndrome .
4. Nystagmus Blockage Syndrome
5. Esotropia arising secondary to central
nervous system abnormalities (in cerebral
palsy for example).
Infantile
Esotropia esotropia with right
Oblique muscle overaction grade 4 (
Pic. Curtsey Dr Sudhir Singh)
Infantile
Esotropia esotropia with right
Oblique muscle overaction grade 4 (
Pic. Curtsey Dr Sudhir Singh)
Infantile Esotropia esotropia with
left Oblique muscle overaction grade
4 ( Pic. Curtsey Dr Sudhir Singh)
Management
When to operate ?
Ing [1] and Helveston, [2] favour a
prescribed approach often involving multiple
surgical episodes whereas others prefer to
aim for full alignment of the eyes.
According to Dutch study (ELISSS) [3]
compared early with late surgery in a
prospective, controlled, non-randomized,
multicenter trial and reported that:Children
operated early had better gross stereopsis
at age six as compared to children operated
late. They had been operated more
frequently, however, and a substantial
number of children in both groups had not
been operated at all.
Surgical dose : you can calculate bySquintMaster
Software.
Caution: If age of child is below 2 years
then take measurement from limbus for
recession as SquintMaster provide
measurement from muscles insertion.
Reference:
1. Ing M.R.; Early Surgical Aignment for
Congenital Esotropia; Ophthalmology, 1983;
90: 132-135
2. Helveston E.M.; Ellis F.D.; Patterson J.H;
Weber, J.; Augmented Recession of the Medial
Recti
3.Simonsz HJ, Kolling GH, Unnebrink K.
Strabismus. 2005 Dec;13(4):169-99
