Increase in the Rate of Acanthamoeba Keratitis
Increase in the Rate of Acanthamoeba Keratitis
Over the past few years, there has been a notable rise in the rate of fungal keratitis. The use of specific types of contact lens solution has been thought to be a contributing cause in some of these patients. Acanthamoeba keratitis is an uncommon corneal infection (previously estimated at around 1 to 2 cases per million contact lens wearers in the United States) that has typically been associated with contact lens use and contact with contaminated water. The authors of this retrospective case-control study took note of a growing rate of this amoebic infection with the report of 55 new cases.
The Association of Contact Lens Solution Use and Acanthamoeba Keratitis
Joslin CE, Tu EY, Shoff ME, et al
Am J Ophthalmol. 2007;144:169-180
Between 2003 and 2006, a total of 55 cases of acanthamoeba keratitis were diagnosed. Of these, 38 had complete information regarding contact lens use (35 were soft lens users). Use of a specific type of contact lens solution (Advance Medical Optics Complete MoisturePlus) was noted in 55% of cases, a much higher figure than the 10% noted in the 39 members of the control group. The authors found that although the use of this solution represented an independent risk factor, it did not account for all of the recent cases of acanthamoeba keratitis. Weakly positive associations were found between the development of acanthamoeba keratitis and poor lens hygiene (reuse of solution, showering with lenses, and rubbing lenses).
Acanthamoeba has been found to be resistant to contact lens solution, especially the specific solution documented in this study. The authors pointed out that while their cases are from a single institution in Chicago, other outbreaks of acanthamoeba keratitis have been reported across the United States. They suggested that other factors are likely in play to explain this increase in the rate of acanthamoeba keratitis. These may include poor lens hygiene, higher microbial load of acanthamoeba, frequency of lens replacement, and contact lens material.
One limitation of this study is that details of the use of contact lenses and solutions depended on recall by the affected patients. Nevertheless, the results suggest a strong association between the use of a specific type of contact lens solution and the development of a rare corneal infection. This outbreak and the prior documentation of an increase in the rate of fungal keratitis underscore the importance of the collaboration between clinical and epidemiologic studies, especially in the study of uncommon disorders.
Abstract
Over the past few years, there has been a notable rise in the rate of fungal keratitis. The use of specific types of contact lens solution has been thought to be a contributing cause in some of these patients. Acanthamoeba keratitis is an uncommon corneal infection (previously estimated at around 1 to 2 cases per million contact lens wearers in the United States) that has typically been associated with contact lens use and contact with contaminated water. The authors of this retrospective case-control study took note of a growing rate of this amoebic infection with the report of 55 new cases.
The Association of Contact Lens Solution Use and Acanthamoeba Keratitis
Joslin CE, Tu EY, Shoff ME, et al
Am J Ophthalmol. 2007;144:169-180
Between 2003 and 2006, a total of 55 cases of acanthamoeba keratitis were diagnosed. Of these, 38 had complete information regarding contact lens use (35 were soft lens users). Use of a specific type of contact lens solution (Advance Medical Optics Complete MoisturePlus) was noted in 55% of cases, a much higher figure than the 10% noted in the 39 members of the control group. The authors found that although the use of this solution represented an independent risk factor, it did not account for all of the recent cases of acanthamoeba keratitis. Weakly positive associations were found between the development of acanthamoeba keratitis and poor lens hygiene (reuse of solution, showering with lenses, and rubbing lenses).
Acanthamoeba has been found to be resistant to contact lens solution, especially the specific solution documented in this study. The authors pointed out that while their cases are from a single institution in Chicago, other outbreaks of acanthamoeba keratitis have been reported across the United States. They suggested that other factors are likely in play to explain this increase in the rate of acanthamoeba keratitis. These may include poor lens hygiene, higher microbial load of acanthamoeba, frequency of lens replacement, and contact lens material.
One limitation of this study is that details of the use of contact lenses and solutions depended on recall by the affected patients. Nevertheless, the results suggest a strong association between the use of a specific type of contact lens solution and the development of a rare corneal infection. This outbreak and the prior documentation of an increase in the rate of fungal keratitis underscore the importance of the collaboration between clinical and epidemiologic studies, especially in the study of uncommon disorders.
Abstract
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