A novel mechanism of increased infections in contact lens wearers

It is well documented that contact lens wearers have much higher incidences of corneal infections compared with those of non-contact lens wearers, although the exact cause(s) of this increased susceptibility has not been identified. A distinct subset of mucins (MUCs) is present on the ocular surface, acting to protect the integrity of the corneal epithelium. This study was performed to determine whether multipurpose contact lens solutions (MPCLSs) can cause increased infections in the cornea by destroying the protective cell-bound mucin layer.

An immortalized human corneal limbal epithelial cell line was treated in the presence of four commonly used MPCLSs or PBS and the expression and release of MUC-16 was assessed. Cells were also cultured with Pseudomonas aeruginosa after MPCLS treatment and internalization of bacteria was assessed by quantitative genomic PCR. Loss of MUC-16 was then correlated with infection rates.

Each of the four commonly used MPCLSs examined in this study differentially affected mucin release. The relative effect was correlated with an increase in infection of corneal epithelial cells by P. aeruginosa.

The results of this study are consistent with the hypothesis that MPCLSs cause increased infections in the cornea by destroying the protective cell-bound mucin layer.