Infection–Inflammation Mismatch In Acanthamoeba Keratitis: A Globe-Threatening Surgical Challenge

To describe a globe-threatening evolution of Acanthamoeba keratitis characterized by infection–inflammation mismatch after microbiological control, highlighting structural complications related to persistent inflammation and anti-amoebic toxicity, and emphasizing the role of timely multidisciplinary surgical intervention to preserve ocular integrity and visual function.

Cornea Department, Barraquer Ophthalmology Centre, Barcelona, Spain.

A 34-year-old woman presented with a 4-month history of severe ocular pain and redness in the right eye. Acanthamoeba keratitis had been confirmed by positive corneal PCR. Best-corrected visual acuity (BCVA) was 0.03. Slit-lamp exam showed marked ciliary injection and a dense stromal ring infiltrate with a paracentral epithelial defect. At presentation, topical therapy included chlorhexidine 0.02%, corticosteroids, atropine, and ofloxacin.

Corticosteroids were discontinued and intensive dual anti-amoebic therapy (chlorhexidine 0.02% and hexamidine 0.1%) was initiated. Microbiological control was achieved; however, persistent stromal infiltration without signs of active infection indicated a secondary inflammatory phase, reflecting infection–inflammation mismatch. Despite cautious steroid reintroduction, a thinning neurotrophic ulcer with a non-healing epithelial defect developed. An amniotic membrane overlay was applied to stabilize the ocular surface, but stromal melt progressed, likely due to sustained immune activation and diamidine toxicity, leading to corneal perforation.

Urgent therapeutic penetrating keratoplasty was required. Postoperative course was complicated by inflammatory cataract and severe ocular hypertension (44 mmHg) refractory to medical therapy. A second-stage combined procedure included cataract extraction with IOL implantation, Paul Glaucoma Implant, and pars plana vitrectomy.

Final BCVA improved to 0.7 with normal intraocular pressure.

Acanthamoeba keratitis may evolve into a surgically complex and globe-threatening disease even after apparent infectious control. Persistent immune activation and anti-amoebic toxicity can induce progressive corneal melt, perforation, cataract formation, and refractory glaucoma. Early recognition of infection–inflammation mismatch, close follow-up, and awareness of clinical red flags—such as persistent stromal infiltration or progressive thinning despite microbiological control—are essential. Coordinated corneal, glaucoma, and vitreoretinal management is critical to optimize both anatomical integrity and visual outcomes.