That possibility has led to a search for drugs to protect susceptible nerves from injury. Several promising candidates are under investigation, including a drug called memantine (Namenda), which is now approved to treat Alzheimer’s, and riluzole (Rilutek), used to treat Lou Gehrig’s disease.
There is growing optimism that what works for one neurodegenerative disease, as these examples suggest, may be helpful for others. For researchers trying to understand the details of what goes wrong in such disorders, glaucoma may offer an easier model to study than a brain disease like Alzheimer’s. The optic nerve is the only nerve that can be examined visually, by peering through the pupil. And the visual system is a relatively compact structure that researchers already understand in great detail.
For now, the only treatments available for glaucoma work by lowering pressure in the eye, either by decreasing the production of fluid or increasing its outflow. Even in patients with normal intraocular pressure and early signs of the disease, lowering pressure has been shown to significantly slow the progression of nerve damage. Most antiglaucoma drugs are delivered as eye drops, which may need to be used once or several times a day. When drops aren’t enough, laser treatments and surgery can be used to allow excess fluid to flow out of the eyes.