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Segmental palsy of the sphincter muscles (arrows). Best
seen on slit-lamp.
.
Right dilated pupil
Right pupil has no light reflex.
Pupils react to accommodation
Note: The arrow represents the light.
The patient (usually a female) has anisocoria with the
enlarged pupil failing to react to light. However, the pupil constricts
in response to accommodation with delayed dilatation (this results in reversal
of anisocoria).
Note: Adie's pupil is bilateral in 15% of cases and
in long-standing cases the pupil may be miosed.
Further examination:
mention you would like to examine the iris on the slit-lamp
for segmental palsies and vermiform movement of the iris
mention that you would like to test the tendon reflexes.
This is absent in 70% of patient (Holme-Adie's syndrome)
Questions:
1. How can one confirm Adie's pupil?
Answer
The iris shows denervation hypersensitivity. A low concentration
of pilocarpine for example 0.1% can cause pupil constriction
in Adie's pupil but not in the normal. However, this test may not
be confirmatory in acute cases.
2. How can you differentiate a dilated pupil from third
nerve palsy from that caused by Adie's pupil or drug-induced?
Answer
In the clinical examination, light responses are absent
in all the three conditions. However, accommodation reflex
will be seen in Adie's pupil but not in the other two conditions.
The mydriasis in third nerve palsy is usually associated with
ptosis and ocular motility abnormalities.
Using 0.1% pilocarpine topically on each pupil, only
the Adie's pupil will constrict. With 1% pilocarpine, both
Adie's pupil and third nerve palsy will constrict but not in drug-induced
mydriasis.
3. What is responsible for the signs seen in Adie's pupil?
Answer
There is denervation of the post-ganglionic supply to
the sphincter pupillae and the ciliary muscle. This may follow
infection such as herpes-zoster or trauma but is usually idiopathic.
The ciliary ganglion has 30 times more neurons for the ciliary
muscle than for the iris sphincter. Thus, following recovery, most of
the sprouting new axons arise from the accommodation cells but may
end up in the iris sphincter (ie. aberrant regeneration). The vermiform
movements represent contractile activity of those iris sectors which
remain connected to the light sensitive neurons.
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