For patients using continuous wear or extended wear contact lenses, replacing lenses at night has no beneficial effect on ocular events compared with monthly lens replacement, a study has found.
However, morning lens replacement significantly reduced the overall rate of adverse events compared with monthly replacement.
The authors of the study say that contact lens wearers on an extended wear or continuous wear schedule “should be advised to minimise lens handling before sleep to reduce the risk of complications.”
A total of 215 individuals were dispensed with silicone hydrogel lenses on a 30-night continuous wear schedule. They were either advised to replace their lenses daily each night before sleeping (n=178 eyes) or each morning after waking (n=252 eyes). Neophytes were required to complete one week of daily wear before commencing continuous wear. A control group (n=191 eyes) was also included in the study. These individuals replaced their lenses monthly.
Led by Jerome Ozkan, University of South Wales, Australia, the team observed a significant reduction in adverse events when lenses were replaced each morning compared with being replaced monthly. They found no such effect when they examined those who replaced their lenses each evening.
Interestingly, when the researchers assessed the handling-related lens contamination of unworn lenses they isolated the bacterium Staphylococcus aureus from the lenses of 35% of the individuals.
“Replacing lenses at night had no beneficial effects perhaps because the benefit of a fresh lens at night might be partially negated by contamination of the contact lens caused by lens handling before eye closure,” suggest the researchers. “Contact lens wearers on an extended wear or continuous wear schedule should be advised to minimise lens handling before sleep to reduce the risk of complications.”