Infectious keratitis: what have we learned?

Contact lenses for correction of refractive error provide for one of the safest and most effective methods of intervention of any of the medical devices. Despite the relatively low incidence of adverse outcomes, when these do occur they may be associated with serious morbidity. Consistent with this risk, albeit relatively low, the industry has made great strides in understanding the complexities of the effect of the lens on the ocular environment, leading to materials and solutions which if used correctly could potentially lower morbidity significantly. Recent outbreaks of unusual adverse events related to multifaceted issues of lens wear, compliance and lens care, have led to a systematic review of contact lenses and their relationship to the ocular environment. This article reviews the data that has emerged in terms of contact lens use, the microbiology associated with their use, the physiology related to potential adverse events and the epidemiology associated with corneal infection secondary to lens wear. The review is intended to dispel assumptions that have been made without sufficient data to support them. Additionally this paper provides a systematic review of current scientific data which is intended to be used in current and future endeavors to lower morbidity even further.