In this contribution the activity of antiglaucomatics - 2% pilocarpine (pH 5,98), 0,5% timoptol (pH 6,58) and 0,005% xalatan (pH 6,83) is emphasized from the view of pH values and changes of the pH values of the rabbit aqueous humor in vitro after their application. The rabbit’s aqueous humor pH is 7,59 - similar to the human healthy eye (7,5 - 7,6). We observed that these antiglaucomatics decrease the aqueous humor pH to the acid levels in the following order: 2% pilocarpine > 0,5% timoptol > 0,005% xalatan. The most significant decrease was measured immediately after the application. From the view of speed of response and effectivity in time achieving the pH of the normal aqueous humor we constate the following order: 0,005% xalatan > 0,5% timoptol > 2% pilocarpine. The changes in pH of the aqueous humor after application of these antiglaucomatics are directly connect with their physiologic function in the eye. Moreover, they also point out the importance of the pH dependence of the antiglaucomatics applicated into the conjunctival sac in the treat-ment of the glaucoma disease.

        Key words: changes in pH of the aqueous humor of the rabbits after application of antiglaucomatics