Abstract
Purpose: :
To compare the effect of rinsing solutions used in emergency treatment of severe eye burns with alkali, we studied their effect on the changes of pH in the anterior chamber of rabbit eyes. Due to a lack of comparative studies we decided to increase accurate information on the effect of emergency treatment with tap water and special solutions found in the market place to treat chemical eye burns. We used a severe alkali eye burn model on freshly enucleated rabbit eyes (ex vivo model).
Methods: :
The 10 mm diameter center of 35 rabbit corneas were burnt by applying filter paper of 10 mm diameter with (25µl ± 1.4 µl) 2 molar NaOH for a period of 20 seconds followed by immediate rinsing with 1000 ml (66 ml/min) of different solutions for 15 minutes according to ANSI recommendations. The anterior chamber pH was monitored using a pH microelectrode of 1.7mm diameter positioned at the level of the endothelium and in the center of cornea. We used for rinsing: tap water, isotonic physiological saline NaCL 0.9%, isotonic phosphate buffer solution, Cederroth eye wash (Cederroth® Sweden), Previn (Prevor® France), Diphoterine (Prevor® France). As reference 5 burnt corneas did not receive any treatment after eye burns.
Results: :
For untreated eyes, the anterior chamber pH increased to 12.28 and after 20 minutes, it dropped to 11.80, yielding a change of ΔpH = 0.47, this is described in the formula [pH drop =ΔpH = Max. pH – Min. pH]. The results in paired t–test were significantly different for none rinsing versus phosphate buffer, tap water and isotonic physiological saline solution, while solutions Diphoterine®, Previn®, and Cederroth® (borate buffer) proved to be more efficient within 15 minutes of rinsing, (p<0.001 for all observations except tap water versus saline solution p=0.75). The anterior chamber pH (Max. pH/ Min. pH= pH after 20 minutes/ ΔpH):
NaCL 0.9% (Max. pH =12.332, Min. pH=11.472, ΔpH=0.86), tap water (Max. pH=11.899, Min. pH=10.696, ΔpH=1.202), phosphate buffer (Max. pH=12.634, Min. pH=11.742, ΔpH=0.892), Diphoterine (Max. pH=12.325, Min. pH=8.635, ΔpH=3.690), Previn (Max. pH=11.621, Min. pH=9.975, ΔpH=1.646), Cederroth eye wash (Max. pH=12.124, Min. pH=9.14, ΔpH=2.984).
Conclusions: :
The initial intervention has a greater effect on the trauma depending on the solution used in the emergency treatment procedure. The best neutralisation of alkali burns were found for Diphoterine®, Cederroth® eye wash solution, Previn®. Phosphate buffer and saline solution 0.9% are much less effective in these results. Water plays an intermediate role.
Keywords: trauma • ocular irritancy/toxicity testing • aqueous