Strabismus - Fundamentals of Clinical Ophthalmology.pdf

CHILDHOOD ONSET OF STRABISMUS
may be of any type but is most commonly
esotropia. The periodicity tends to be in cycles of
about 24 hours and if untreated, it may become
constant within 6 months. Children with this
condition are often older, with good fusion. They
experience diplopia on the days when the
strabismus is present and have binocular single
vision when the eyes are straight. Surgery is
associated with a high degree of success and
indicated if the condition has remained static.
Figure 4.7 A child with convergent strabismus from
congenital ptosis disrupting binocular vision
Iatrogenic esotropia
Prolonged occlusion of one eye (for example,
following eyelid surgery) may result in sensory
deprivation, disruption of binocular vision and
occlusion esotropia. Such patients may have
never previously had a strabismus but may have
had a history of uncorrected hypermetropia or a
family history of strabismus. It may also occur in
the treatment of anisometropic amblyopia or
trauma causing eyelid swelling. 13 This condition
is mirrored clinically in some cases of congenital
ptosis (Figures 4.7 and 4.8). Awareness and early
recognition of this condition are essential.
Reduction in the period of occlusion can reverse
this condition.
Functional esotropia
It is well known that emotional state may
influence the degree of strabismus present in a
patient. It can occur following surgical correction
where the eyes have been straight. There may be
worsening of esotropia with diplopia, even in the
presence of fusion.
Esotropia without fusion potential
A significant number of children with
congenital esotropia do not achieve peripheral
fusion and stable ocular alignment even though
treated early in their visual development and left
with small residual squints. Since the majority of
children with congenital esotropia would have
had ocular alignment by age 2 it is difficult to
identify this group. In the siblings and family of
Figure 4.8 A child with concurrent blepharophimosis
and right convergent strabismus
some of these children it is our experience that
some have defects in their binocular vision and
quality of stereopsis and fusion, suggesting there
is a defect in the development that remains as
the basis for this group. Asymmetrical OKN
is present in these cases. The one eye may
dominate, with the second eye contributing to
the overall visual field. Subsequent consecutive
divergence squints may occur.
Esotropia in cerebral palsy
Strabismus and indeed visual abnormalities
are common in hydrocephalus and cerebral palsy.
Although esotropia is more common, other
ocular deviations reflecting a different neurologic
basis may be the reason for presentation.
The inclination to correct these cases deserves
more attention. Parents often state that with the
straightening of eyes the child’s general performance
improves. It is more likely that the
improved appearance of the child results in the
child being treated with more consideration by
teachers and their peers.
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