Stromal involvement, poor BCVA linked to failed Acanthamoeba keratitis treatment

Cornea. 2011;30(4):435-441.

Treatment of Acanthamoeba keratitis was more likely to fail in female patients older than 50 years with stromal involvement and poor visual acuity, a study found. Contact lens wear also may contribute to the infection.

"Early diagnosis before stromal involvement remains critical for a favorable outcome in [Acanthamoeba keratitis], and one should have a high index of suspicion for this disease in patients wearing soft contact lenses," the study authors said.

The retrospective study included 59 patients diagnosed with Acanthamoeba keratitis between January 2004 and December 2008. Mean patient age was 34 years (range, 12 to 75 years). Fifty-seven patients (97%) wore contact lenses, and two patients (3%) did not wear lenses.

Failed treatment was defined as patients requiring penetrating keratoplasty and/or having best corrected visual acuity worse than 20/100 at final follow-up. Mean follow-up was 341 days (range: 11 days to 1,068 days).

Onset of Acanthamoeba keratitis occurred most frequently in the summer and least frequently in the winter. Mean time to diagnosis was 39 days (range: 4 days to 355 days).

After treatment, 16 patients (31%) had BCVA worse than 20/100; 11 of these patients required PK. Initial BCVA was 20/50 or better in 23 patients (45%). BCVA was 20/25 or better in 23 patients (45%) and 20/100 or better in 35 patients (69%) at final follow-up or before PK.

Univariate analysis showed that age older than 50 years, female sex, initial visual acuity worse than 20/50, evidence of stromal involvement and confirmed tissue diagnosis correlated most significantly with treatment failure. A larger prospective study is needed to corroborate this finding, the authors said.