There are many types and subtypes of glaucoma the open angle and the one which is narrowed or blocked angle glaucoma. There are many drugs used to manage these types of glaucoma. I have found out that adrenergic agonists(sympathomimetic) /alpha agonists are used to treat OPEN ANGLE glaucoma. My question is
1. why are these adrenergic agonists like PHENYLEPHRINE used in glaucoma when in fact they mimic the sympathetic response they cause pupillary dilation which increases intraocular pressure which is contraindicated in glaucoma, please explain how it can help in glaucoma if it causes pupil dilation? (one possible reason would be the inhibitory effect to norepinephrine by alpha2 receptors)
I have also found out that beta blockers(sympatholytic) suppress the sympathetic response causing pupil constriction decreasing intraocular pressure which helps in glaucoma. Cholinergic drugs/parasympatholytic mimic parasympathe response also helps by pupil constriction and can be used for open and narrow glaucoma
2. is my understanding correct? which drugs are used for which type of glaucoma? What is in open angle and closed angle which makes some drugs contraindicated to one and not the other
3.why are benzodizepines not for narrow angle glaucoma, does sedation constrict the pupil and decrease intraocular pressure? why can it be used for open angle glaucoma?

I think you might get a response from a glaucoma specialist on here:

https://health.groups.yahoo.com/group/glaucoma/

Joyce

hey thanks joyce the site was great its an exclusive yahoo groups for glaucoma!