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Study: Lens bioburden may contribute to increased infection risk with extended wear
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SEATTLE – In a comparison of extended and daily wear of a silicone hydrogel, researchers concluded that the greater frequency of lens bioburden with extended wear and a stagnant post-lens tear layer may increase the risk of infection and inflammation, according to a study presented at the American Academy of Optometry meeting.
Loretta Szczotka-Flynn OD, PhD, reported at an academy-sponsored press conference that extended wear with lotrafilcon A was shown to have a decreased frequency of corneal staining when compared to daily wear with multipurpose solution use, but increased frequency of corneal staining when compared to daily wear and hydrogen peroxide use.
Loretta
Szczotka-Flynn
A total of 423 patients were evaluated over the course of 1 year.
“About 11% of extended wear and 32% of daily wear subjects had repeated episodes of at least moderate staining over 12 months,” according to the study abstract. However, “when stratified by solution use, 9% of daily wear peroxide users and 39% of daily wear multipurpose solution users had repeated episodes of staining, and only the multipurpose solution group differed in staining from the extended wear cohort.”
The lens bioburden was cultured at selected visits in the 1-year follow-up, Szczotka-Flynn reported at the press conference.
A significantly decreased rate of lens bioburden in the PHMB-preserved group was seen, with no difference in the extended wear and peroxide group. With lid bioburden, the opposite was true, she said; there was more bioburden on the daily wear group.
“We believe the coalescent punctate staining, which is mechanical in nature, and the increased bioburden is probably what’s driving the increased rate in infections in extended wear,” Szczotka-Flynn concluded.
Disclosure: This study was sponsored by the National Eye Institute and Alcon Research Ltd.