In a double-blind study [with glaucoma patients] no significant difference was found in intraocular pressure control, mean pressure or comparative binocular intraocular pressure difference between pilocarpine in Adsorbobase compared to pilocarpine in 0.5% hydroxypropylmethylcellulose solution. Intraocular pressure control was achieved on fewer than 60% of visits using pilocarpine twice daily in either of the 2 vehicles. While pilocarpine retained some residual hypotensive effect 12 h after application, twice-daily dosage with the solutions tested gave inadequate control for clinical usefulness.