The first line of glaucoma treatment is the use of prescription eyedrops. Several classes of medications are effective at lowering IOP and thus preventing optic nerve damage in chronic and neonatal glaucoma. Beta blockers (e.g. timolol), carbonic anhydrase inhibitors (e.g. acetazolamide), and alpha-2 agonists (e.g. brimonidine tartrate) inhibit aqueous humor production. Miotics (e.g. pilocarpine) and prostaglandin analogues (e.g. latanoprost) increase the outflow of aqueous humor.
It is important for patients to inform their doctors of any health conditions they have or any medications they take, including over-the counter drugs. Certain drugs used to treat glaucoma are not prescribed for patients with pre-existing conditions. The drugs prescribed to treat glaucoma all have side effects, so patients taking them should be monitored closely, especially for cardiovascular, pulmonary, and behavioral symptoms. Each medication lowers IOP by a different amount, and a combination of medications may be necessary. To ensure that IOP is lowered sufficiently, it is important that patients take their medications and be monitored regularly. IOP should be measured three to four times per year.
Normal-tension glaucoma is treated by reducing IOP to less-than-normal levels, on the theory that overly susceptible optic nerves are less likely to be damaged at lower pressures. Research underway may point to better treatments for this form of glaucoma.
Attacks of acute closed-angle glaucoma are medical emergencies. IOP is rapidly lowered by successive deployment of acetazolamide, hyperosmotic agents, a topical beta-blocker, and pilocarpine. Epinephrine should not be used because it exacerbates angle closure.
Trabeculectomy, to open the drainage canals or make an opening in the iris, can be effective in increasing the outflow of aqueous humor. This surgery is usually successful, but the effects often last less than one year. Nevertheless, this is an effective treatment for patients whose IOP is not sufficiently lowered by drugs and for those who can’t tolerate the drugs.
Laser peripheral iridotomy is a procedure used almost exclusively to treat narrow angle glaucoma. It involves creating a small opening in the peripherial iris that allows aqueous fluid to drain from behind the iris directly to the anterior chamber. This procedure typically result in “opening up” the narrow angle between the iris and the cornea, in essence converting a narrow angle into an open angle.
Argon laser trabeculoplasty is usually recommended when medications have not been able to sufficiently control IOP, although it is increasingly advocated as primary therapy for patients who are not good candidates for the use of glaucoma medications or who cannot use eyedrops. In this procedure, the beam of an argon laser is directed at the trabecular meshwork. Typically about 180° of the trabecular meshwork is treated with laser spots. As a result of this procedure, the drainage of aqueous fluid out of the eye increases, thus lowering IOP.
Gene therapy may also be part of future treatments. A mutation in the gene myocilin is believed to cause most cases of juvenile glaucoma, and 3-4% of adult glaucoma. As of 2001, researchers are investigating drugs that inhibit myocilin production. The drug therapy would not just treat IOP, but also could be used before glaucoma’s onset.
Vitamin C, vitamin B1 (thiamine), chromium, zinc, and rutin may reduce IOP.
Patients using alternative methods to attempt to prevent optic nerve damage should be advised they also need the care of a traditionally trained ophthalmologist or optometrist who is licensed to treat glaucoma, so that IOP and optic nerve damage can be monitored.
About half of the people who have glaucoma are not aware of it. For them, the prognosis is not good, and many of them will become blind. On the other hand, the prognosis for treated glaucoma is excellent.