Corneal calcification is a common problem in severe
inflammation, chronic
glaucoma, renal disorders and other diseases with disturbed
calcium and
phosphorus metabolism. The pathogenesis of corneal calcifications in ocular diseases is not yet completely understood. We present a model of an induced corneal calcification by local treatment. In a double-masked experiment 16 rabbits underwent
eye burn of one cornea followed by immediate rinsing (160 ml) with isotonic
phosphate buffer (n=8) or
saline solution (n=8) three time a day for 16 days. Tissues were excised,
shock frozen and cut into 10 microm slices, freeze dried and coated with evaporated
carbon. In the
phosphate buffer group an early onset of corneal opacification occurred resulting in completely white corneas after 16 days, combined with corneoscleral ulceration. The other group showed similar corneal erosion and a little corneal ulceration, but no opacifications. The opacifications of the
phosphate buffer group could be identified as calcifications by direct measurements of
calcium and
phosphate (by energy dispersive X-ray analysis on corneal samples). In conclusion, inappropriate application of
phosphate leads to uncontrolled calcifications of the cornea after severe
burns to the eye. This reflects clinically observed calcifications after
eye burns and possibly the adverse side effects of
phosphate buffered
eye drops being applied in ophthalmology.