Corneal calcification after chemical eye burns caused by eye drops containing phosphate buffer

Abstract

Purpose Chemical burns with calcium containing corrosives as well as irrigation with phosphate buffer solutions after eye burns bear the risk of corneal calcification. The aim of this study was to evaluate the correlation between the occurrence of corneal calcification after chemical injuries and the usage of phosphate buffer containing local therapeutics. Methods We reviewed the data of 179 patients who have been treated in the University Eye Clinic Aachen, Germany, between 1941 and 2000. Only when the corrosive did not contain calcium and when the initial irrigating solution did not contain phosphate buffer, respectively, were patients included in the study. The cases were analyse, if the patient was treated with phosphate buffer containing eye drops/ointment during the first 7 days of hospitalization or as an out-patient, and if corneal calcification was visible by slit-lamp examination during the follow-up. Statistical analysis was performed using Fischer's exact test. Results 152 eyes were included. From 63 eyes treated with phosphate buffer containing eye drops, 31 eyes (49%) developed corneal calcification. From 89 eyes treated without phosphate buffer containing eye drops, only 23 eyes (26%) developed corneal calcification. The two-sided p-value of Fischer's exact test is 0.0036. Conclusion During follow-up after chemical eye burns, eye drops containing phosphate buffer double the risk of corneal calcification. We recommend avoiding these agents in order to prevent the burned cornea from additional opacity. Substances containing phosphate buffer are listed in this article.