Abstract
Purpose: :
To compare the corneal tolerance of three topical ocular treatments (Dicloced® (Dicloabak®), Tobradex® and Dicloced®+Tobradex®) in albino rabbits, after multiple daily ocular instillations for 28 days.
Methods: :
Three treatments were instilled five times daily (50 µl each) spread over 8 hours for 28 consecutive days in both eyes of three New Zealand rabbits : 1/ Dicloced® an NSAID (preservative-free 0.1% diclofenac), 2/ Tobradex® an aminoside (0.3% tobramycin) associated with a steroid (dexamethasone 0.1%), 3/ Dicloced® + Tobradex® administered 10 minutes apart. A saline solution (NaCl 0.9%) was administered in the same conditions as negative control. Ocular evaluations (conjunctiva, cornea, anterior chamber and iris) were performed with a slit-lamp using the McDonald-Shadduck’s scale before the first administration then weekly before the first instillation of the day. The pachymetry was recorded seven days before the first administration then weekly before the first daily instillation using a confocal microscopy (HRT-II). At the end of the study (day 29), animals were euthanised and corneas were sampled and fixed for histology analysis.
Results: :
For all treatments no effect was observed for conjunctiva, cornea, anterior chamber and iris but after measurement of the whole cornea thickness it was observed : no modification for the animals administered with Dicloced® (NS p>0.05, n=6), a significant decrease for the animals administered with Tobradex® (-13%, p=0.02, n=6) and also a significant decrease for the animals administered with Dicloced®+Tobradex® (-19%, p=0.004, n=6). No microscopic findings were observed after histology analysis of the cornea.
Keywords: cornea: stroma and keratocytes • microscopy: confocal/tunneling • inflammation