Role of contact lenses in acanthamoeba keratitis

ABSTRACT

The present work was planned to study the role of contact lenses in Acanthamoeba keratitis. The study included two groups, 100 subjects each [contact lens and non-contact lens users]; 50% of each group were suffering from keratitis, while the others were asymptomatic. Ocular samples [corneal scrapings or swabs], contact lenses and lens care systems [storage containers and solutions] were examined for the presence of acanthamoeba using cultureand staining techniques. The isolation of acanthamoeba was achieved by the cultivation of the previous samples on non-nutrient agar overlaid with E. coliat 37C. Acanthamoebae were identified according to their morphological characters and the negative flagellation test. Acanthamoeba was identified in cultures of different specimens obtained from 20 subjects out of 200. The majority of acanthamoeba positive cases [90%] were contact lens users. Acanthamoeba was isolated more frequently from patients with keratitis and was not isolated from any asymptomatic non-contact lens users. Cultivation of the contact lenses was associated with high rate of acanthamoeba detection compared with the other sources of samples. From the present study, it was concluded that acanthamoebae are expected to be found in the contact lenses, their storage containers and rinsing solutions, which may predispose tokeratitis in contact lens users. Precise disinfection of contact lenses, cleaning of lens storage containers and the use of sterile rinsing solutions have a primary importance to prevent acanthamoeba contamination of contact lens care system