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Case 31
by Professor Chua Chung Nen
A 35 year-old woman was referred by the casualty doctor
three days after a road traffic accident because of complaint of ocular
discomfort (Figure 1 and Figure 2). She was previously fit and well and had
no medical history of note.
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Figure 1. Side
view of the patient
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Figure 2. Eyelid closure.
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a.
What is the most likely cause for her ocular discomfort?
Conjunctival exposure and
poor eyelid blinking as a result of paralysis of the orbicularis
oculi. This is the result of cut to the zygomatic branch of the facial nerve (see picture below).
An anatomical specimen showing
the zygomatic branch (red arrow).
b. How would you manage this patient?
The management is the same as ocular treatment of lower facial nerve
palsy. She has good Bell's phenomenon so the risk of exposure keratitis at sleep is reduced. The ocular discomfort
could be improved by regular application of artificial tear and the wearing
of glasses to reduce the effect of wind on tear evaporation. Eye ointment is
applied at night with eyelid tapping to decrease conjunctival
dryness.
As the wounds are clean cut and well-apposed, accurate nerve
regeneration is likely. The management is mainly supportive until the orbicularis oculi function
returns.
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