The patients were admitted to hospital, and the aqueous pilocarpine drops were discontinued for 24 hours. All other antiglaucomatous medications, if prescribed, were unaltered throughout the trial.On the second day of admission a controlled phasing was done 4 times a day with a Goldmann applanation tonometer. On the third day of admission the tensions were taken in a similar manner, with 9 eyes receiving aqueous pilocarpine drops 4 times a day and 10 eyes receiving oily pilocarpine drops twice a day. The percentage concentration of aqueous and oily pilocarpine was the same as the patient had been taking before the trial. Topical application of pilocarpine was withheld on the third day and the intraocular pressures were not recorded. On the final day the tensions were recorded with 9 patients receiving oily pilocarpine drops and 10 patients receiving the aqueous form.The intraocular tensions were measured on the same tonometer by the same examiner, and the mean of 3 readings was taken. The examiner was unaware of the type of pilocarpine instilled, and the patients were asked to note any difference in the 'first' and 'second' medications. Results