The consequences of delayed intervention when treating chemical eye burns

Background Immediate rescue intervention for chemical and thermal eye burns can save the victim's sight. We studied the anterior chamber pH changes immediately after ex vivo eye burn to investigate the effects of immediate and delayed intervention. Methods Twenty three enucleated pigs eyes were burnt with 500 mu l 2 mol NaOH for 20 s using a cylinder with a diameter of 10 mm. The corneas were rinsed in groups with 1015 ml ordinary tap water at a flow rate of 1.125 ml/s for 15 minutes immediately after burning (n=6), and after a delay of 20, 40, and 60 s (n=5, 3 and 4 respectively). One group of eyes was not rinsed (n=5). The intraocular pH was defined at the start as Cymin pH' and the end as Cymax pH'(Delta pH=max pH-min pH). Results The intraocular pH increased sharply in the untreated eyes from a min pH of 6.76 +/- 0.55 to a max pH of 11.85 +/- 0.24, yielding a Delta pH of 5.08. The difference between the timepoint at which the pH began to increase and the speed of change was significantly different between the unrinsed and rinsed eyes, and there was an inverse correlation between this and the time at which rinsing started (p < 0.001). The best results were achieved in eyes rinsed immediately after burning (p < 0.001). The pH in the eyes not rinsed immediately increased rapidly, and in all groups in which rinsing was delayed the max pH was markedly higher (p=0.093). Conclusions Immediate emergency rinsing is essential in eye burn victims. Appropriate rinsing solutions and treatment facilities in the form of rinsing stations where chemical burns may occur must be available at the workplace. Tap water is also effective as a rinsing solution.