ABSTRACT
BACKGROUND: The long-term prognosis of patients with chemical eye burns depends on immediately rinsing the eye after the trauma. The chemical properties and tolerance of currently used rinsing solutions were examined. METHODS: NaCl 0.9%, Ringer lactate, balanced salt solution (Aqsia), phosphate buffer, tap water, and Previn were analyzed. The buffer capacities were determined by titration with HCl and NaOH. The osmolarity of the solutions and the osmolarity of 100 healthy and 100 alkali burned porcine corneas were determined by means of freezing point depression. 56 enucleated porcine eyes were burned and rinsed with NaCl solutions of different osmolarities (0-1200 mosmol/l), Previn, NaCl 0.9% or phosphate buffer, respectively. The different swelling behaviors were determined by pachymetric measurements, and the resulting corneal osmolarity after irrigation was assessed. The effect of Previn as a hyperosmolar solution in comparison with isoosmolar phosphate buffer was examined on 10 healthy human eyes. RESULTS: Only phosphate buffer and Previn show high buffer capacities. The osmolarity of the healthy/burned porcine corneas was 329+/-61/1203+/-289 mosmol/kg. Except for Previn (862+/-3 mosmol/l), all solutions are hypo- or almost isoosmolar in comparison with the healthy cornea. Rinsing of the burned corneas causes swelling in all groups in inverse proportion to the osmolarity of the solution. Thus, the lower the solution's osmolarity, the stronger the swelling reaction of the cornea. The resulting corneal osmolarity following rinsing behaves proportionally to the osmolarity of the rinsing solution. Therefore, a high osmolarity of the rinsing solution correlates with a high corneal osmolarity. No long-term effects in healthy eyes were observed after rinsing with Previn or phosphate buffer. CONCLUSION: Corneal thickness and osmolarity are significantly correlated to the osmolarity of the rinsing solution. Corneal edema dilutes the agent in the stroma. Therefore, we recommend solutions with low osmolarity (tap water) or high buffer capacity (Previn) for the initial post-trauma irrigation.
