Abstract
Purpose: :
Solution-induced corneal staining (SICS) remains a contact lens complication, despite the evolution of improved lens materials and multipurpose solutions. The study purpose was to evaluate corneal staining and epithelial barrier function in lens wearers after 8 hours of wear.
Methods: :
This was a randomized, double-masked, controlled study in primarily young, full-time daily wearers of soft contact lenses. New balafilcon A lenses were soaked in 1) polyhexamethylene biguanide-based multipurpose solution, and 2) non-preserved saline solution as a control, then worn for 8 hours prior to corneal measurements. Corneal staining was evaluated with the modified Efron Grading Scale, and barrier function was characterized by the fluorescein penetration rate (Pdc) and stromal amount (in arbitrary fluorescence units) measured with an objective, scanning fluorometer.
Results: :
A total of 26 subjects completed the study. Total staining scores were 6.0 (± 2.4) and 4.3 (± 1.8) scale units (0 - 20 scale) for the test and control eyes, respectively (p = 0.001, one-sample t-test). The mean dye diffusion rates, Pdc (± SD) were 0.057 (± 0.04) and 0.058 (± 0.04) nm/sec for the test and control eyes, respectively (p = 0.81, one-sample t-test). Penetrated dye amounts were 150.3 (± 112) and 138.7 (± 104) arbitrary fluorescence units for the test and control eyes, respectively (p = 0.638, one-sample t-test).
Conclusions: :
Use of an objective, quantitative method suggests that only mild physiological perturbations occur at 8 hours of wear under these conditions, with no significant difference in barrier function between test and control eyes. Test eyes had more staining than control eyes at 8 hours, but the difference was low and likely not clinically significant.
Clinical Trial: :
http://www.clinicaltrials.gov NCT01015768
Keywords: contact lens • cornea: epithelium • cornea: tears/tear film/dry eye