Effects of rigid gas permeable contact lens solutions on the human corneal epithelium

In this investigation, the effects of three rigid gas permeable (RGP) contact lens wetting and soaking solutions, Boston Advance Conditioning Solution, Boston Conditioning Solution, and Allergan Wet-N-Soak Plus, were tested on the human corneal epithelium. Thirty subjects participated in three experimental sessions, during which one eye received three drops of one of these RGP solutions, while the other eye served as a control. After 10 and 30 min, corneal staining was graded in 5 areas and the eyes were photographed for a digitized analysis of staining. Our results indicate that corneas exposed to Boston Advance Conditioning Solution demonstrated significantly more fluorescein staining than control eyes at both 10 and 30 min by both methods of analysis, whereas corneas treated with the other two solutions were not significantly different from controls. The increased corneal staining noted with Boston Advance Conditioning Solution may be caused by the presence and concentration of the preservative, 0.0015% polyaminopropyl biguanide. An unforeseen result of this experiment was the relatively large number of subjects exposed to Boston Conditioning Solution and Allergan Wet-N-Soak Plus who had more corneal staining in the control eye. This may suggest that the two RGP solutions served as a barrier to fluorescein, protecting the epithelial cells from staining.