AIM:To investigate the appropriate methods to establish corneal alkali chemical injury on rats.

METHODS:The rats(n=87)were randomly divided into three groups. Corneal alkali injury was induced by placing 1mol/L NaOH soaked filter paper on the limbus of right cornea for 20 seconds(group A, n=34)or 40 seconds(group B, n=23), and on the central axis of the right cornea for 40 seconds(group C, n=30)respectively. Corneal transparency, corneal ulceration, and corneal neovascularization were observed and recorded under slit- lamp biomicroscope on day 7 post-operation.

RESULTS: Incidence of corneal ulceration, corneal perforation and positive rate of corneal fluorescein staining in limbal corneal injury groups(group A and B)were significantly higher than that of central corneal injury group(group C)(P<0.05). Incidence of corneal ulceration and corneal perforation in group B was significantly higher than group A(P<0.05). Corneal neovascularization was observed in all three groups.

CONCLUSION: Corneal alkali burns induced by 3mm diameter central cornea injury are fit for the study of corneal neovascularization, while those induced by limbus injury for 20 seconds are fit for the study on limbal stem cells deficiency.