Effect of vehicle on pilocarpine-induced ocular hypotension

The effect of 1.4% polyvinyl alcohol and castor oil vehicles on pilocarpine-induced hypotension was studied in 50 patients with open-angle glaucoma. Diurnal tension curves showed that the mean intraocular pressure was lower and the maximum diurnal variation smaller during the treatment with oily drops of 2% and 4% pilocarpine instilled 2-3 times daily than when 2% and 4% pilocarpine in polyvinyl alcohol was instilled 3-4 times daily. The differences were statistically significant. In long-term treatment no marked pilocarpine tolerance developed in cases treated with oily drops of pilocarpine. It is concluded that in the treatment of patients with open-angle glaucoma, the hypotensive effect of pilocarpine in an oily vehicle instilled 2-3 times daily is greater and more even than that of pilocarpine of corresponding strength in polyvinyl alcohol administered 3-4 times daily.