Purpose : To report the clinical characteristics, predisposing factors and therapeutic outcome in a series of patients diagnosed with acanthamoeba keratitis(AK).

Materials and Methods: The data was collected from the clinical records of patients admitted with infective keratitis at Regional Institute of Ophthalmology, Trivandrum from December 2012 to May 2013. In this retrospective case series analysis, medical and microbiology records of forty consecutive patients with acanthamoeba keratitis(AK) were reviewed and analyzed. All cases with a micro biologically proven acanthamoeba corneal infection either by direct microscopy or by culture following standard protocols were included for analysis.

Results: Among the 40 patients,thirty four patients had coexistent fungal keratitis and four were isolated AK. Sixty percentage of patients had a predisposing factor with history of trauma or contact with foreign bodies. No patients in our series were contact lens users. Twenty two patients (55%) had central corneal ulcers with size greater than 3mm.Twenty three patients (57.5%) had a best corrected visual acuity(BCVA) less than 6/60 at presentation. Majority (80%) of these patients responded well with adequate healing of ulcer and visual improvement(60%) to a combination therapy of Chlorhexidine 0.02% and Neomycin (98%).

Conclusion: Till recently acanthamoeba infections were considered as a rare cause for infective keratitis compared to fungal and bacterial keratitis in this part of the world. This recent report highlights a significant rise in occurrence of Acanthamoeba keratitis among our corneal ulcer patients. Most of the patients in our series lacked the typical clinical characteristics of acanthamoeba keratitis. High index of clinical suspicion  helped us in the accurate diagnosis of this co existing mixed parasitic infection. Addition of specific  amoebicidal drugs like  Chlorhexidine and Neomycin or Poly hexa methylene biguanide  to the conventional anti fungal therapy gave very good response with favorable therapeutic outcome in majority of these patients, as demonstrated in our series.