A new paradigm for corneal wound healing research:: The white leghorn chicken (Gallus gallus domesticus)

Purpose. To evaluate the chicken cornea as a model for corneal wound healing research. Methods. We conducted studies on normal chicken corneas and on corneas following mechanical debridement and photorefractive keratectomy (PRK). Results. The chicken cornea possesses six distinct layers that resemble the layers of the human cornea, including a substantial Bowman's layer measuring 5.2 +/- 0.3 mum thick. Reepithelialization time was 44.8 +/- 1.1 hours with a sliding rate of 75.3 +/- 3.2 mum/hour following mechanical debridement and 54.4 +/- 2.8 hours with a sliding rate of 63.3 +/- 3.2 mum/hour for PRK-treated corneas. Biomicroscopic haze post-PRK peaked at 4-6 weeks and regressed until 20 weeks post-PRK. Histologic and clinical observations of wound healing strongly paralleled that noted in humans. Conclusion. The chicken cornea's morphology and wound healing response render it a useful model for corneal wound healing investigations.