The effect of topical pilocarpine on pulsatile ocular blood flow

Ocular blood flow is considered an important factor in determining the extent of visual damage occurring in primary open angle glaucoma (POAG). The effect of topical pilocarpine, a parasympathomimetic vasodilator, on the pulsatile ocular blood flow (POBF) in POAG subjects was studied. A pneumotonometer linked to the Langham Ocular Blood Flow System recorded the intraocular pressure (IOP) pulse from which POBF was calculated. Measurements were taken from 18 POAG subjects treated with both G pilocarpine and G timolol, 2 weeks after withdrawing G pilocarpine and again 1 week after reinstituting full treatment. Recordings from 20 POAG patients treated with only G timolol were taken as control values. There was no significant difference in the IOP or POBF between the controls and POAG patients on dual therapy. Furthermore when G pilocarpine was temporarily withdrawn there was no significant change in POBF despite a significant rise in IOP. The results imply that aqueous pilocarpine has no direct effect on the pulsatile component of ocular blood.