Common eye ointments linked to glaucoma implant swelling

Japanese researchers have cautioned patients with Preserflo MicroShunts against using petrolatum-based eye ointments

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15 January 2026

Researchers from Nagoya University have cautioned glaucoma patients with Preserflo MicroShunts against using petrolatum-based eye ointments – especially when the device is exposed outside the conjunctiva.

Writing in Graefe's Archive for Clinical and Experimental Ophthalmology, scientists describe three cases of Preserflo MicroShunts swelling after patients used petrolatum-based eye ointments.

In the first case, a 54-year-old male received a MicroShunt implantation in his right eye for secondary glaucoma.

After rupture of the conjunctiva and exposure of the MicroShunt, 0.3% ofloxacin ophthalmic ointment was prescribed. When the device was removed five days later, it was swollen compared to an unused MicroShunt.

In the second case, a 51-year-old male who received a MicroShunt implementation in his left eye was prescribed 0.1% dexamethasone ophthalmic ointment after undergoing needling.

The exposed device, which was swollen and friable, broke during removal – with one fin detaching.

In the third case, after a 59-year-old female experienced a bleb leak following MicroShunt implementation, she was prescribed 0.3% ofloxacin ophthalmic ointment. The swollen MicroShunt also fractured upon removal.

“This case series, together with the in vitro experiments, showed that physical contact with an ophthalmic ointment causes the MicroShunt polymer to significantly swell,” the scientists highlighted.

In tandem with the case series, the researchers conducted laboratory experiments where unused Preserflo MicroShunts were exposed to petrolatum-based eye ointments – resulting in “marked swelling.”

The scientists highlighted that swelling of the implant can compromise device integrity – as illustrated by the device fracturing following exposure to ointment in both laboratory and clinical settings.

“Ophthalmic ointment should not be used in cases where MicroShunt is exposed. It may also be better to avoid ophthalmic ointment use when conjunctival integrity is compromised and bleb leak is present,” the authors noted.