Collagen shields exacerbate ulceration of alkali-burned rabbit corneas

J. S. Wentworth, C. A. Paterson, J. T. Wells, N. Tilki, R. S. Gray and M. D. McCartney
Department of Ophthalmology and Visual Sciences, University of Louisville School of Medicine, KY 40292.

OBJECTIVE--To determine the impact of collagen shields on ulceration of rabbit corneas after alkali burn. METHODS--After a 60-second 2N sodium hydroxide burn to rabbit corneas, 24-hour collagen shields were placed on the corneas daily for 21 days; control corneas did not receive collagen shields. The extent of corneal ulceration was documented daily for 21 days by slit-lamp examination of treated and control eyes. Three separate studies were performed using collagen shields from two commercial sources. RESULTS--In the three studies, corneas in the collagen shield-treated eyes began to ulcerate sooner than those in the control group; the corneas in collagen shield-treated eyes also began to perforate sooner. At 21 days after alkali injury, the mean (+/- SE) corneal ulceration score in the collagen shield-treated rabbits was 4.1 +/- 0.17 (descemetocele formation) compared with 2.7 +/- 0.28 (midstromal ulceration) in controls. This difference was significant at P < .005. CONCLUSION--Collagen shield treatment results in marked acceleration of corneal ulceration and perforation after alkali injury.