Confocal microscopy of the rabbit conjunctiva and cornea and the response to wounding

Purpose: To determine the cellular organization and appearance of the conjunctiva by confocal microscopy and the cellular response of the conjunctiva and cornea to experimental wounds. Methods: The study was performed using a prototype tandem scanning confocal microscope with a 20x applanating objective. New Zealand white rabbits were used. A Ixlmm burn was performed on the conjunctiva and cornea using a 1 sec application of a handheld electrocautery. Corneal and conjunctival incisions (0.5x2mm) were made and the healing process was examined at 1, 3, 6, 24, and 72 hrs after the surgical procedure. Results: Normal conjunctival epithelial cells, goblet cells, subepithelial excretory glands, and muscular structures in the lamina propria were well defined prior to wounding. Corneal epithelium, stromal cells, nerves, and endothelium were also easily visualized. After the conjunctival burn, an active inflammatory cell response occurred after 1 hr and decreased by 24 hrs. Acute vessel reaction started 4-6 hrs after the burn; new vessels had begun to form at 24 hrs and had penetrated the damaged area by 72 hrs. Accessory lacrimal glands and goblet cells did not reappear. After the corneal burn, active inflammatory cell penetration and epithelial migration started at 2-4 hrs. Prominent nerves were detected around the bum at 4 hrs. After 24 hrs, keratocyte processes could be seen extending toward the wound and the nuclei of these cells were more reflective. After the conjunctival cut, vessel reaction and penetration into the wound were observed after 4 hrs. After the corneal incision, epithelialization was completed after 24 hrs. Conclusions: Confocal microscopy provides an opportunity to investigate the anatomical structure of the ocular surface and development of the response to wounding.