Effects of calcium channel blockers on rabbit corneal endothelial function.

The effects of calcium channel antagonists and agents that alter intracellular Ca2+ mobilization on corneal endothelial function have been examined. All experiments, except where specifically designated, were performed in the continuous presence of extracellular Ca2+. Verapamil (at 50 microM) increased the swelling rate of corneas bathed in normal Ringer solution whereas nifedipine and diltiazem (both up to 100 microM) were without effect.

Perfluorocarbon effects on rabbit blood-retinal barrier permeability.

Studies have been made of the effects of intravitreal perfluoro-n-octane on the permeability to fluorescein of the blood-retinal barrier in rabbits. At day 1 after injection, there is increased aqueous humor fluorescence that reflects the physical disturbance to the eye following injection. From that time through 7 weeks, there is no evidence of any overt toxicity to the blood-retinal barrier.

Blood-ocular barrier permeability and electroretinogram after intravitreal silicone oils of varying composition.

Silicone oils, used as long-term retinal tamponades, cause retinal toxicity that may be related to certain ingredients. Specific additives, proven to increase corneal endothelial permeability, were added to a purified oil, and placed into the vitreous of rabbits to assess their effects on the retina. Oils were exchanged for vitreous at constant intraocular pressure to 1 ml oil volume.

Drug interaction with intraocular lenses of different materials.

The uptake and washout kinetics of four drugs representing different classes of ophthalmic medications were measured in intraocular lenses of different materials. The materials ranged from hydrogel lenses to poly(methyl methacrylate) (PMMA), Acrysof (acrylic/methacrylic), and two types of silicone lenses (Chiroflex and AMO SI-18NB). Uptake was determined after seven days of immersion in a large volume of Ringer's solution containing drug concentrations that equaled those found in aqueous humor 30 minutes to one hour after topical administration.

Influence of vehicle and anterior chamber protein concentration on cyclosporine penetration through the isolated rabbit cornea.

The transcorneal penetration of cyclosporine A has been determined from each of three vehicles across isolated cornea into simulated aqueous humor containing either 50 mg % protein (0.5 mg/ml; as found in a normal eye) or 5000 mg % protein (50 mg/ml; as found in an inflamed eye). Cyclosporine entered the corneal epithelium and stroma/endothelium as well as passed through the cornea from an alpha cyclodextrin vehicle.