Because glaucoma is really a number of different disorders and affects everybody differently, there is no singular definitive treatment. The purpose of glaucoma treatments is ultimately the same in every case and that is to prevent the deterioration of the optic disc and preserve normal vision. This is achieved by lowering the intraocular pressure. The level of the intraocular pressure is determined by the balance between the production of the aqueous humor and the outflow of the aqueous humor.
Imagine a tap and drain in an overflowing bathtub. In order to stop the water spilling out of the tub you can either turn the faucet down to decrease the water entering the tub, or improve the drainage out of the tub by increasing the rate of flow down the drain. Pills, eye drops, laser treatment, or standard surgical techniques all help reduce elevated intraocular pressures by either improving the drainage of aqueous humor or slowing down the rate of production.
At the beginning of treatment, your ophthalmologist will place you on a single medication. Your response to therapy will be closely monitored and, if necessary, a combination of the medications will be used to control your intraocular pressures and stabilize your vision. Your ophthalmologist will continue to check you frequently, until you achieve a stable situation and find medications that work best for you.
Because intraocular pressures are not always constant, your ophthalmologist will continue to check your intraocular pressure readings while you are on medication and occasionally when you are off your medication. Also, over time, people can become resistant to their medications and the intraocular pressures creep back up to the levels they were at before medication, so your ophthalmologist will monitor this as well.