Life on contact lenses: Exploiting a modern habitat

There are an estimated 125 million contact lens wearers across the world, and the majority experience few complications; however, it is well known that contact lens wear is a risk factor for microbial keratitis (infection of the cornea of the eye). Owing to the ubiquitous distribution of micro-organisms, it is extremely di cult to prevent them from colonizing contact lens storage cases. Bacteria, fungi and protozoa have all been found in contact lens storage cases; these micro-organisms can adhere to the contact lens, which then acts as a vector to transport the microbes on to the surface of the eye. Bacteria such as Pseudomonas aeruginosa, fungi such as Fusarium solani and the protazoan parasite Acanthamoeba–to name but a few–can cause infection of the corneal epithelial cells, which, if untreated, can lead to blindness. It is therefore essential that wearers clean and disinfect their contact lenses and storage cases e ectively to minimize the risk of infection.