Strabismus - Fundamentals of Clinical Ophthalmology.pdf

Transient skew deviation
CHILDHOOD ONSET OF STRABISMUS
Figure 4.21 Congenital fibrosis syndrome is
characterised by a bilateral ptosis, divergent squint,
eyes in depression, and inability to elevate them.
There is markedly restricted vertical movement and
attempts to depress the eyes result in further
divergence
Described in neonates, this condition is rare
and transient. It has been described as a transient
palsy in obstetric trauma in otherwise healthy
neonates. By contrast, persistent skew deviation
of the eyes, although rare, is found in association
with brainstem disease. Skew deviation has to be
distinguished from primary inferior oblique over
action (see chapter 4, p26). Skew deviation with
brainstem disease can present as the classical
“setting sun” sign, with tonic looking down of
the eyes and lid retraction most commonly seen
with hydrocephalus or kernicterus.
demonstrated to have laxity of the superior
oblique tendon. Anomalies of the reflected
tendon of superior oblique include:
●
●
●
●
a redundant tendon
a misdirected tendon inserting on the nasal
border of superior rectus
an attenuated tendon inserting to the undersurface
of Tenon’s capsule, or
an absent tendon.
Absence of superior oblique is occasionally
associated with craniofacial synostosis. 23–25
Benign paroxysmal tonic upgaze
of childhood
This recently described syndrome in contrast
to the “setting sun” sign is an apparently benign
oculomotor disorder with onset in early life. 26
Characteristic features include episodes of
sustained upgaze, with downbeating saccades in
attempted downgaze which are difficult to
sustain below the primary position. There are
apparently normal horizontal movements. Sleep
gives relief. The cases we have seen have
otherwise normal neurological findings apart
from ataxia. We noted the absence of
deterioration during observation over 15 years,
with improvement of symptoms in some patients.
Vertical movement disorders of
early infancy
Isolated inferior oblique palsy
This is an extremely rare form of uniocular
muscle paresis. It is usually congenital, rarely
traumatic and is diagnosed with the findings of
hypertropia with a head tilt toward the side of
the hypertropic eye. Convergence in upgaze
(A pattern) contrasts with the exotropia on
upgaze (V pattern) seen in Brown’s syndrome
(Figure 4.20, see also chapter 7, p78) and helps
in the differential diagnosis of inability to elevate
the eye in adduction.
Congenital fibrosis syndrome
This is an autosomal dominant condition
associated with abnormal neuronal migration
and fixed hypodeviation of both eyes (Figures
4.21 and 4.22). Head tilt with chin elevation,
and a spastic convergence on attempted lateral
or upgaze are also associated features.
Recent studies of these cases in our
department and Westmead Children’s Hospital
have demonstrated abnormalities of the lateral
ventricle and basal nuclei suggesting that the
fibrosis of ocular muscles is due to static
pathology associated with a developmental
central nervous system disorder. These findings
41