Fungal keratitis appears to be on the rise among contact lens wearers

A recent outbreak of Fusarium keratitis in contact lens wearers has raised questions regarding the background rate of Fusarium-related keratitis and other types of fungal keratitis in this population. An investigation by the Centers for Disease Control and Prevention identified Bausch and Lomb's ReNu with MoistureLoc multipurpose solution as a significant risk factor. The purpose of the current study was to determine the effect withdrawal of that product from the market had on the rate of fungal keratitis infection among contact lens wearers. They found that the number of Fusarium cases did return to previous levels after the product was removed. However, the number of other filamentous fungal keratitis cases, although small, seems to have increased among refractive contact lens wearers.

Investigators reviewed 695 fungal keratitis cases seen at 10 tertiary medical centers between 2001 and 2007. A total of 283 cases involved the use of contact lenses. The quarterly number of Fusarium keratitis cases among contact lens wearers rose significantly during the period ReNu with MoistureLoc was on the market and peaked during the second quarter of 2006, the last quarter the product was commercially available, before quickly returning to baseline. An increase in the quarterly number of non-Fusarium, culture-positive fungal keratitis cases among both contact lens wearers and non- contact lens wearers was also seen, starting in the third quarter of 2005 and remaining at an increased quarterly frequency through the remainder of the study period; however, this trend was only significant for refractive contact lens wearers. The reasons for this are unclear.

The authors conclude that this outbreak and the recent spike in Acanthamoeba cases demonstrate the need for establishing ongoing surveillance systems to monitor the number of contact lens-related corneal infections.