Bilateral Acanthamoeba Keratitis Secondary to Contaminated Contact Lens Suction Applicators: A Rare Case of Accessory-Mediated Transmission.

INTRODUCTION: Acanthamoeba keratitis (AK) is a sight-threatening corneal infection primarily associated with contact lens wear. While lens and case hygiene are frequently emphasised, auxiliary tools such as suction applicators remain a neglected vector for transmission. This report highlights a case of bilateral AK where a contaminated suction applicator served as a likely vehicle for infection. CASE PRESENTATION: A 57-year-old female long-term rigid gas permeable (RGP) lens wearer presented with a 2-week history of severe, bilateral ocular pain, redness, and photophobia. Slit-lamp examination revealed bilateral dendritic epithelial disruption and mild anterior chamber activity. The patient reported good contact lens hygiene but used a rubber suction applicator for daily lens use, which was routinely rinsed with tap water. Diagnosis was confirmed via corneal scrapings and polymerase chain reaction (PCR) for Acanthamoeba DNA. PCR analysis of washes from the suction device's lumen also returned positive for Acanthamoeba. Following a course of topical propamidine isethionate (Brolene) and topical chlorhexidine 0.02%, the keratitis fully resolved over several months. Final visual acuity was 6/12 (pinhole) in the right eye and 6/5 in the left. CONCLUSION: This case underscores a critical blind spot in patient education regarding accessory hygiene. Suction applicators can act as a reservoir for Acanthamoeba and provide a route for inoculation onto the ocular surface. We recommend that these tools undergo regular replacement and be handled with strict no-water protocols. Clinicians should specifically audit and advise on the hygiene of handling tools, particularly in RGP and scleral lens populations.