I have a question about the use of eye drops for glaucoma. I think the first choice would be latanoprost, but is it okay to use timolol as a second choice, when the first one did not work well and I wanted to add one more eye drops? Are there any not-to-do combinations use among latanoprost, timolol, and Trusopt (Dorzolamide hydrochloride)? Also, Aiphagan and Glanatec are sometimes used in human ophthalmology, but is there any case in canines and felines which these two eye drops are used on top of the three eye drops above?