CONJUNCTIVAL TISSUE EXAMINATION IN SEVERE EYE BURNS - A STUDY WITH SCANNING ELECTRON-MICROSCOPY AND ENERGY-DISPERSIVE X-RAY-ANALYSIS

Background: Longlasting inflammation is a major problem in treatment after severe eye burns and may find expression in an altered elemental composition of the conjunctiva. Particulate contamination of biological tissue induces such inflammatory processes. In the anterior eye segment, trauma or subsequent therapy may give rise to such contamination. Scanning electron microscopy and energy-dispersive X-ray analysis are able to detect traumatic residues of submicron size and changes of the elemental composition. Methods: Conjunctival specimens from first-time peridectomy of three healthy and nine severely burnt-eyes were examined with scanning electron microscopy and energy-dispersive X-ray analysis. The samples were prepared as cryo- or paraffin sections, mounted on carbon blocks and coated with evaporated elemental carbon. Results: The samples of healthy conjunctiva showed higher concentrations of Na, P and CI. These elements showed lower concentrations in conjunctival stroma of burnt eyes excised before the 20th day after trauma than in material obtained subsequently. In two burnt conjunctival specimens there was severe traumatic contamination with Ca in Ca(OH)(2) and CaO burns, and in one case the traumatic substance was Si, in a peroxide plus silicone spray burn. In the remaining six cases, particulate contamination with Fe, Al, Ni, Zn, Cu, Ti and other substances was present in the burnt conjunctivas, while no contamination was detected in the specimens of healthy conjunctivas. Conclusions: The origin of the contaminant particles is assumed to be the trauma itself and the subsequent therapy. These investigations stress the importance, for clinical purposes, or early peridectomy and contamination-free therapy.