Rabbits wore either melimine-coated or control contact lenses with or without adherent
P. aeruginosa in their left eyes for 24 hours, while the right eye served as a nonlens control. Before lens insertion, lenses were examined for particulate matter, physical damage, and inversion. Rabbits were reexamined after 6 hours of lens insertion to monitor retention of lens and in case of any lens loss, the respective type of lens with or without adherent bacteria was reinserted. Rabbits were administered subcutaneous 0.01 mg kg
−1 buprenorphine. Contact lens fit was assessed using slit-lamp biomicroscopy, including lens centration, corneal coverage, and tightness. All rabbits had a detailed ocular examination and photographs taken by a single trained optometrist. Slit-lamp biomicroscopy was performed using a Nikon photographic slit lamp (Nikon FS-3V; Tokyo, Japan), which provided up to ×32 magnification. Detailed anterior segment examinations were carried out, including sodium fluorescein (Chauvin Pharmaceuticals Ltd., Surry, UK) staining. Wratten #12 filter (Bausch & Lomb, Rochester, NY, USA) was used in conjunction with cobalt blue filter to excite fluorescence. Photographs were taken and then graded, using the CCLRU grading scale,
46 by a single trained masked optometrist who recorded details of corneal and conjunctival parameters (
Table 1). Ocular examinations were performed at baseline and immediately after lens removal at 24 hours and at 48 hours (after 24 hours of no lens wear). The ocular variables assessed and scores given during each examination are listed in
Table 1. All rabbits were closely monitored during lens wear for any indication of stress by examining their movements, alertness, gait, behavior, vocalizations, and respiration. After 24 hours, lenses from rabbits' left eyes were aseptically collected in 2 mL sterile PBS and processed to determine viable bacterial count. If MK developed, the animal was immediately euthanized and the left cornea was collected to determine viable bacterial count. All rabbits wore contact lenses for up to three occasions if MK did not develop. If MK developed, the rabbits were euthanized. A minimum of 2 weeks of wash out was provided between each lens wear for rabbits to recover from any effects of lens wear.