Adrenergic activity and intraocular pressure.

Systemically-administered noradrenaline lowers intraocular pressure; isoproterenol, similarly administered, has an intraocular pressure-raising effect. Unless extremely low doses are used, these effects will be marked by opposite changes in arterial perfusing pressure. Intraocular pressure-regulating mechanisms carry both alpha- and beta-receptors. Stimulation of alpha-receptors decreases intraocular pressure, while stimulation of beta-receptors increases intraocular pressure. Intraocular pressure is under tonic sympathetic influence.