The main focus of contact lens design lies in the ability of the lens to be biocompatible with the eye and surrounding tissues. Lens design also focuses on choosing materials that are resistant to protein deposition and to bacterial adhesion. Choosing these materials can be difficult since the wear of contact lenses promotes the formation of a protein layer on the lens surface, mediating bacterial adhesion.

Severe complications of contact lens wear, such as microbial keratits, can occur when contact lenses replace eyeglass use and are misused. The risk of infection is coupled with the use of different lens materials and exposure to microorganisms. Visual loss can occur due to scarring or perforation of retinal tissues as well as an increased rate of ulcers and eye disease.

For these reasons, disposable contacts were created: the new lenses were developed to reduce the risk of infection associated with contact lenses worn for successive overnight periods (extended wear). While it may seem that the risk of infection associated with contact lenses that are disposed of frequently is less, lens wearers of disposable and extended wear lenses are both at risk of infection.

To decrease this risk, lens designers must be focused on detecting and diminishing characteristics favoring protein deposition and therefore bacterial attachment to the lens.

In this study, Staphylococcus aureus was quantitatively measured on disposable and extended wear lenses to compare characteristics leading to bacterial attachment.  Staphylococcus aureus is one of the most frequent agents of disposable contact lens-associated infections.  Therefore, the comparison of microbial adherence to both high and low surface tension lenses may provide insight into how bacterial adhesion can be reduced in future lens designs.

Research Advisor: Beverly J. Brown, Ph.D., Nazareth College