Is glaucoma curable?

No. The answer depends on how you define curable. We don't eliminate glaucoma with today's therapies, and we currently cannot restore vision that is permanently lost due to glaucomatous damage. However, we lower the intraocular pressure through medications, laser, or surgery in order to slow down or halt the rate of glaucoma progression so that you can outlive losing your sight.
Controllable. Glaucoma is treatable, not really curable - like high blood pressure. Treatments include topical medications, oral medications, laser treatments or surgical procedures. Constant monitoring is required to ensure the condition is controlled adequately and that is does not progress.
Yes. The purpose of treatment is to save the optical nerve from damage and to normalize the pressure inside the eye. This can be done mostly by surgery.
Usually controllable. Most types of glaucoma have no symptoms in the early stages, and are not curable in the usual sense that treatment is required for a short time and can then be stopped. Most cases can be controlled with medications, usually eyedrops, and sometimes laser treatment or surgery. Some types of glaucoma can be "cured" with a single laser treatment, but those patients require ongoing monitoring too.