Effects of daily and overnight wear of hyper-oxygen transmissible rigid and silicone hydrogel lenses on bacterial binding to the corneal epithelium: 13-month clinical trials.

PURPOSE: For 14 years, the U. S. Food and Drug Administration (FDA) and eye care practitioners have strongly discouraged patients from sleeping in contact lenses. In the past 9 months however, the FDA has approved three new hyper-oxygen transmissible lenses for up to 30-night extended wear. Is this a great advance or another clinical triumph of hope over experience? What should the public know? What should patients do? METHODS: Our research group has studied all three new lenses in prospective, randomized, masked, parallel clinical trials in a single center. As an outcome measure, we looked at whether lens wear caused more bacterial binding to surface corneal cells. RESULTS: Compared with conventional lens use, the new lenses caused no or only small increases in bacterial binding in either daily or extended wear. Furthermore, the increases seen stratified with known infection risks by both lens type (hard or soft) and wearing schedule. Indeed, early epidemiologic reports indicate that this new generation of lenses may reduce lens-related microbial infection risks by 10- to 40-fold. CONCLUSION: This represents a true clinical paradigm shift of the first magnitude in safety of contact lens wear. Taken together, this data suggest that patients will soon replace their current, conventional lenses with this new generation of materials for any schedule of wear.