Corneal Staining and Physiological Compromise After Eight Hours of Soft Contact Lens Wear

The purpose of this study is to assess corneal staining and to measure the relative corneal epithelial "barrier" function (the degree to which the cornea can prevent penetration of colored sodium fluorescein dye into the eye) after 8 hours of wear with a known soft contact lens and multipurpose lens care solution combination.

This investigation will evaluate corneal staining and epithelial barrier function after eight hours of contact lens wear, which is past the peak staining time and more typical of daily lens wear time. A silicone hydrogel lens and multipurpose solution combination shown to induce significant corneal staining ( e.g. equivalent Grade 3 out of Grade 4 scale) will be used to evaluate potential corneal compromise. The study will be a prospective, single-center, double-masked, contralateral, daily wear investigation in adapted soft contact lens wearers. After a three day washout period (without lens wear, lenses will then be worn on one day for eight hours. Corneal staining and barrier function will be determined for a regimen and a saline control situation for each subject. Staining will be graded using the Efron Grading Scale, and permeability data will be estimated as the fluorescein penetration rate, Pdc in nm/sec for the test and control condition.