How many days does it take to find out if timolol eye drops are helping my dogs glaucoma? He gets 2 drops/day?

Just found out our 10 year old dog has glaucoma in 1 eye. Vet escaped the room before giving me much info. I have no idea how far it has progressed. We live in a rural area so have no specialist to take him to. Should we wait until the eye drops are all used up and then see the vet again, or take him to another vet? Usually our vet is very good, must have been busy that day.