SOLUTIONS CONTAINING MIOTIC AGENTS - EFFECTS ON CORNEAL TRANSENDOTHELIAL ELECTRICAL POTENTIAL DIFFERENCE

Background: Anterior chamber miotic solutions are widely used during a nterior chamber surgery. We examined the effects of solutions containi ng miotic agents such as carbachol and/or acetylcholine on corneal end othelial pumping activity. Methods: We monitored, in vitro, the transe ndothelial electrical potential difference of isolated rabbit corneal endothelial preparations. As controls, we used solutions without mioti cs. Results: We found that a solution containing 55 mM acetylcholine a nd minimal amounts of salts (Miochol E) maintains transendothelial ele ctrical potential difference some 30% above control levels for up to 4 h. Two other solutions, one including balanced salts and 0.55 mM carb achol (Miostat), the other a mixture of 0.19 mM carbachol and 55 mM ac etylcholine plus minimal salts, are adequate to maintain the potential difference at control levels. Lastly, a solution with acetylcholine b ut without any salts (Miochol) greatly decreases the potential differe nce, to 30% of the control level, in 100 min. Conclusion: Our results indicate that: (1) 55 mM (1%) acetylcholine stimulates the endothelial electrical potential difference; (2) addition of 0.19 mM (0.003%) car bachol negates the stimulatory effect of acetylcholine; and (3) absenc e of electrolytes severely depresses the endothelial electrical activi ty.