Pathogenesis of contact lens-associated microbial keratitis

Abstract

Sight-threatening microbial keratitis associated with contact lens wear remains a serious concern for patients, eye-care practitioners, and the contact lens industry. Several decades of research and some major advances in lens and solution technology have not resulted in a decline in disease incidence. Here, we offer a perspective on the complex pathogenesis of microbial keratitis, the factors that have prevented a better understanding of this disease, and new approaches being used to tackle this important clinical problem.

Figure 1

Lens-wearing murine model for investigation of microbial keratitis

Figure 2

Schematic model of steps in the pathogenesis of P. aeruginosa keratitis. In order for bacteria to gain access to the corneal stroma without a full thickness epithelial defect (e.g. no scratch), the following steps are required; Step 1) bacteria survive within post-lens environment, and interact with and adhere to the corneal epithelium, Step 2) bacteria traverse the multilayered epithelium, Step 3) bacteria cross/breach basement membrane, and Step 4) for visible pathology, an inflammatory response and/or bacterial damage to the stroma are required.