Background: Pupillary disorders following varicella infections are rare and few cases have been reported which were only partially pharmacologically tested.
Materials and methods: A 5-year-old boy presented with a left-sided dilated and unreactive pupil, 3 months before he had suffered from chickenpox and in the course of the acute disease developed anterior uveitis which was treated with local prednisone and mydriatics. The pupil remained dilated despite discontinued medication, light reaction was absent and accommodation was impaired. Pilocarpine supersensitivity was an indication against a lesion of the sphincter muscle and reduced response to cholinesterase inhibitors (physostigmine) pointed towards a postganglionic lesion.
Conclusions: It is probable that a varicella virus infection of the short ciliary nerves and the ciliary ganglion caused anterior uveitis and a postganglionic parasympathetic nerve lesion, clinically presenting as a tonic pupil. According to cases previously reported an irreversible nerve lesion has to be assumed.