DIVERGENT SQUINT

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					DIVERGENT SQUINT
Concomitant divergent squint (exotropia) is
characterised by outward deviation of one eye while
the other eye fixates.
Clinico-etiological types
It can be classified into following clinicoetiological
types:
1. Congenital exotropia. It is rare and almost always
present at birth. It is characterised by a fairly large
angle of squint, usually alternate with homonymous
fixation in lateral gaze, and no amblyopia.
2. Primary exotropia. It is a common variety of
exodeviation (unilateral or alternating). It presents
with variable features. It may be of:
  Convergence insufficiency type (exotropia greater
for near than distance),
  Divergence excess (exotropia greater for distance
than near) or
  Basic non-specific type (exotropia equal for near
and distance).
It usually starts as intermittent exotropia at the
age of 2 years. It is associated with normal fusion
and no amblyopia. Stereopsis is usually absent.
Precipitating factors include bright light, fatigue, illhealth
and day-dreaming. If not treated in time it
decompensates to become constant exotropia (Fig.
13.15).
3. Secondary (sensory deprivation) exotropia. It is a
constant unilateral deviation which results from longstanding
monocular lesions (in adults), associated
with low vision in the affected eye. Common causes
include: traumatic cataract, corneal opacity, optic
atrophy, anisometropic amblyopia, retinal detachment
and organic macular lesions.
4. Consecutive exotropia. It is a constant unilateral
exotropia which results either due to surgical overcorrection
of esotropia, or spontaneous conversion
of small degree esotropia with amblyopia into
exotropia.
Fig. 13.15. A patient with primary exotropia

				
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posted:9/16/2012
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Description: Common Eye Disease