Microbial Keratitis in Contact Lens Wearers

Microbial keratitis (MK) is an inflammation of the cornea with sight-threatening potential. It can lead to serious visual impairments followed by permanent visual loss if untreated. The predisposition factors for the MK include ocular surface disease, ocular trauma, ocular surgery, contact lens (CL) wear and systemic diseases. CL wear is one of the most significant predisposition factor for CL related MK [1-5]. A number of CL complications such as mechanical, hypoxic, immunologic and hypersensitivity reactions mimic infectious keratitis. The prevalence of MK has increased ever since the 1970s when soft CLs were introduced and is gradually increasing over time. About 43% of the corneal ulcers are mainly due to soft CL wear [6]. CL related MK is caused by bacteria, fungi, parasites and viruses. Among the microbes causing the MK, fungal keratitis accounts for about 50% of all cases of culture-proven MK in some developing countries. Fungal outbreak caused by Fusarium in CL wearers in 2005 -2006 and the Acanthamoeba outbreak in 2007 have alerted the eye care community and public to focus their attention on the CL related MK. Globally about 140 million people wear CLs for correcting refractive errors. About 3.5 million people have begun to wear CL every year but 2-3 million people discontinue CL wear at about the same time [7]. About 41 million people wear CLs in