Case of a large, movable bacterial concretion with biofilm formation on the ocular surface

To report a case with a large movable bacterial concretion formed on the ocular surface without biomaterials.

Interventional case report. A 74-year-old woman with left eye pain and injection was referred to us. She had a past history of scleral patch graft for necrotizing scleritis after pterygium removal and mitomycin C instillation on her left eye 7 years before. On present examination, a 2.5- to 3.0-mm yellowish-white calcification-like mass was present on the nasal sclera and cornea, and it moved slightly with blinking. The anterior chamber was shallow, and cornea was suspected to be perforated under this object.

This yellowish-white mass was surgically removed. Pathologic examination demonstrated that the specimen was not a calcification but a biofilm formation by many gram-positive bacilli with neutrophils. Corynebacterium was highly suspected as the causative agent of this unusual mass because of the earlier culture of the discharge before referral.

The current case demonstrates that bacterial biofilms can be formed on the ocular surface without the involvement of biomaterials.