• A randomized, double-masked trial of various concentrations of timolol maleate ophthalmic solution (0.1%, 0.25%, 0.5%, and 1.0%) vs placebo demonstrated that all concentrations of timolol effectively lowered intraocular pressure (IOP). A 0.5% solution of timolol was as effective in reducing IOP as the 1.0% concentration. Blood pressure, visual acuity, and pupillary diameter were not altered significantly by any concentration of timolol tested during this study. There was a dose-dependent decrease in resting pulse rate with increasing concentrations of timolol. No objective signs of drug intolerance were found on external ocular examination, nor were any subjective symptoms elicited on questioning the subjects. Timolol applied topically twice daily in concentrations of 0.1% to 0.5% appeared to be an effective and safe ocular hypotensive agent.
Zimmerman TJ, Kass MA, Yablonski ME, Becker B. Timolol MaleateEfficacy and Safety. Arch Ophthalmol. 1979;97(4):656-658. doi:10.1001/archopht.1979.01020010312004