• Topical 0.125% and 0.25% clonidine hydrochloride were compared with 2% pilocarpine hydrochloride and a placebo in a double-masked crossover study. Both strengths of clonidine had an ocular hypotensive effect similar in magnitude and duration to pilocarpine. Clonidine in both concentrations also significantly lowered systemic blood pressure. Further studies will be needed to establish the value and safety of clonidine in the treatment of glaucoma.
Hodapp E, Kolker AE, Kass MA, Goldberg I, Becker B, Gordon M. The Effect of Topical Clonidine on Intraocular Pressure. Arch Ophthalmol. 1981;99(7):1208-1211. doi:10.1001/archopht.1981.03930020082006