No abstract

Thirty-six albino rabbits, randomly divided into six groups, were used to study their ocular tolerance to (a) 0.25 and 0.50% Timoptol^® preserved with 0.01% benzalkonium chloride, (b) 0.25 and 0.50% Timoptol-LP^®, a gel-forming solution preserved with 0.012% benzododecinium bromide, and (c) 0.25 and 0.50% Timabak^® unpreserved in the ABAK^® eyedrops dispenser. All eyedrops were applied in the right eye for 60 days. A clinical follow-up with slitlamp examination and break-up time evaluation was performed for 2 months. At the end of the experimentation, the animals were sacrificed and their eyes enucleated for histological analyses of the conjunctiva and cornea. There was no significant difference in the clinical examination between each group, except for the break-up time evaluation between Timoptol and Timabak at each concentration which was better with the unpreserved timolol. Histological results showed a significant difference in the corneal stroma edema between preserved and unpreserved timolol. This study confirms that using unpreserved timolol may be beneficial for the long-term treatment of glaucomatous patients as it increases tear film stability and decreases epithelial permeability and stromal aggression of the cornea.

The purpose of this experiment was to study in vivo the dynamic behavior of the lymphocyte in the retinal circulation. We developed a new technique capable of visualization of lymphocyte motion in the retinal and choroidal vessels using a rat model. Live cells freshly removed on a donor animal were labeled by a simple method using fluorescein isothiocyanate. Labeled cells were injected systemically into another animal. Retinal images were reconstituted on a video screen with a scanning laser ophthalmoscope (SLO) utilizing the argon green laser excitation wavelength (514.5 nm) to detect cell fluorescence. Lymphocytes were clearly seen and followed in the retinal vessels. Some slowed down in the capillary system, or even stopped for a few seconds, or were definitively caught in it. Labeled cells remained visible after circulating several times. A method was developed for in vivo visualization of lymphocytes in the retinal circulation. This method has the potential for application in the study of lymphocyte cell behavior under physiological as well as pathological conditions.