Correspondence - ICO Library

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Binocular Vision & Inferior Oblique Muscle Palsy with ‘Paradoxical’ V-Pattern Strabismus FIRST Quarter of 2011
Strabology Quarterly© E. Khawam, MD and D. Fahed, MD Volume 26 (No.1)
A Medical Scientific e-Periodical Pages 51-60
b. Head Turn: commonly seen, to the
shoulder of the opposite side placing the eye
in the field of the lesser vertical deviation,
away from the vertical field of fixation of the
IO muscle, placing the affected eye in
abduction.
c. Abnormal Chin Posture: less
commonly encountered than head tilt. In esodeviation
with an A-pattern to the deviation,
the patient may assume a chin-up posture to
avoid the esodeviation in upgaze. In A-exotropia,
the patient may assume a chin-down
posture to avoid exodeviation in down-gaze.
7. Forced Head Tilt Test
(Bielschowsky’s Sign): The head must be
tilted to the opposite shoulder in order to
cause maximal vertical deviation. With tilting
to the opposite shoulder, both extorters of the
eye in the opposite side are stimulated. Since
the IO muscle is paretic, its elevating action
cannot offset the depressing action of the IR
muscle, resulting in increasing hypotropia of
the affected eye.
8. Raising-Eye Phenomenon of the
Fellow Eye in Abduction: The mechanism of
this phenomenon is as follows: in adduction of
the affected eye, excessive innervational input
is sent to the paretic IO muscle in order to
balance that eye vertically. Therefore, a
corresponding, equal, excessive innervation
goes to its yoke SR muscle via Hering’s Law.
This increased innervational input to the SR of
the contralateral eye in abduction causes
upshot or rising of that eye.
9. Duction versus Version: In palsy of
an extraocular muscle, the action of that
muscle improves on duction compared to its
action on version. A characteristic that does
not pertain to mechanical restrictions.
CASE REPORT
This is a 67-year-old woman referred to
us because of diplopia and right hypotropia of
3-years duration (Figure 3 A, Below and 3 B,
Next Page).
Figure 3 A (Khawam & Fahed): Our patient in 8 of the 9 cardinal gaze positions.
Figure 3 B (Khawam & Fahed): Our patient in Bielschowsky Head Tilt Test.