Acquired Corneal Neuropathy and Photoallodynia Associated With Malposition of an Ex-PRESS Shunt.

PURPOSE: Corneal neuropathy is a recently described disease process that is not well understood and is likely underdiagnosed as a result. This is the first reported case of an acquired corneal neuropathy associated with malposition of an Ex-PRESS shunt.

METHODS: A single case report.

RESULTS: We report the case of a 50-year-old man with a history of multiple procedures for glaucoma who subsequently developed photoallodynia and corneal neuropathy in association with malposition of an Ex-PRESS shunt in the peripheral cornea. Laser confocal microscopy (HRT3/RCM) of the cornea showed the presence of neuromas, decreased nerve density, and a significant increase of dendritiform immune cells consistent with our diagnosis. Initial treatment with steroid pulse therapy did not result in decreased inflammation or symptomatic improvement leading to surgical explantation of the shunt. One month after surgery, there was noticeable improvement in the patient's pain and photoallodynia (approximately 40%) as well as the abnormalities seen on confocal microscopy.

CONCLUSIONS: We hypothesize that poor Ex-PRESS shunt positioning can act as a nidus for corneal inflammation, resulting in corneal neuropathy and lowering of the nociception threshold.