A comparison of the pupilloconstrictor effect of pilocarpine solution administered to the conjunctival sac as a single drop or as a continuous infusion in normal subjects.

Pilocarpine was administered into the conjunctival sac of normal volunteers by single-drop administration or by continuous infusion of a solution to the inner canthus by means of a fine Silastic tube. Using pupilloconstriction as a measure of response it was shown that infusion with a 0-01 per cent solution of pilocarpine was as effective as a single drop of 0-5 per cent pilocarpine. The response to the single drop was faster at onset. It was demonstrated that at pH 7-2 pilocarpine was more effective than at acid pH. The infusion method is simple to use, comfortable for long periods, has potential for reducing the need for frequent drop administration and for reducing the total amount of drug administered, and could be used for drugs other than pilocarpine.