They are (relatively) expensive.

Your eye doctor should be the best source.

If your IOP is consistently at its "target" level, your quality of
life is acceptable and the side effects are acceptable, then there is
probably little reason to change from what you are taking.

Personally, I almost never use anything but a prostaglanding analog --
one of those "ridiculously expensive" drops -- as a "first line drug"
on my glaucoma patients.  In layman's terms, "they rule" and are a
Godsend for my patients -- much like timolol was when all we basically
had was pilo and epinephrine.

Forget pot.  Its use in the management of glaucoma is nil.

Glaucoma is a progressive disease and treatment often needs to be
changed to manage; Timoptic may have worked for you years ago but
would not work for you today.  Is brimonidine three times a day
working? Or has your doctor recommended an new drug because you need
more control?  One benefit of the newer drugs is once a day dosing.
So even if three times the cost, your cost per day is the same.
Sometimes your particular disease needs more than one drug to be
controlled.

I find it fascinating you are whinging about price when your vision is
at stake.

Prostaglandins are expensive as there was a huge cost in getting them
to market and the manufacturers need to get a return on investment.
Prostaglandins are the only drug available that gets the required 30%
drop in pressure needed  to prevent progression of the disease. On top
of this, it is used ONCE per day at night, which in my opinion is not
only more efficient use of time but less of a PIA and more likely to
sustain compliance by patients. Next, there is the benefit of adding a
second string drug to increase efficacy.

My best advice is to stop stuffing around playing amateur ophthal and
listen to a real one who actually knows his job.

dr grant