Please do your research about the multifocal lens being considered. Make sure you have spoken with some friends or relatives that have already had it. Very important since there is no way to "try out" these type of lenses.
Regarding the glaucoma, if it is well controlled on just one med then the actual surgery need not be altered much at all. In my practice I almost always bring the glaucoma patients to be seen about 5pm the day of the surgery so check the pressure. I personally often stop the xalatan for a few months after surgery and use another glaucoma drop instead but many doctors don't do that. Basically, if your surgeon is experienced and excellent, the chances of success are very, very high.
If glaucoma is involved, I would have a complete work up by a glaucoma specialist with his advice. Cataract surgery may have a positive affect on eye pressure but increases your chances of retinal detachment.
I lost the sight during retinal detachment surgery following cataract surgery. My optic nerve did not survive the surgery because of advanced glaucoma. A fact casually omitted to me prior to my cataract and retinal detachment surgery .
I would weigh all the factors and educate myself to ask all appropriate questions. It's your eyes...your responsibility.