Glaucoma is an eye disease in which the pressure in the eye causes a loss of vision by damaging the optic nerve. One of the main treatment strategies for patients with glaucoma is to lower the pressure inside the eye. There are several classes of medications that are effective in doing that; the different classes use different mechanisms to achieve that goal. Beta blockers are one medication class commonly used to treat glaucoma; beta blockers lower eye pressure by decreasing the amount of fluid produced by the eye. Beta blockers can lower blood pressure, lower the heart rate and cause problems in people who have asthma or other breathing problems or in people with diabetes. Some beta blockers--called selective beta blockers--are associated with fewer of these kinds of side effects. There are several different beta blockers available; these eye drops can be used alone or in combination with another class of glaucoma medication.
Timolol Maleate
Timolol is a non-selective beta blocker eye medication. While timolol may have more generalized side effects, it tends to be more effective than selective beta blockers. According to the University of Illinois Eye & Ear Infirmary, timolol lowers eye pressure by 20 to 35 percent, whereas the selective beta blockers are less effective at lowering the eye pressure (15 to 25 percent). There are several versions of timolol available on the market produced by several pharmaceutical companies. The standard timolol formulation is used twice a day; however, there is another type called timolol-XE that is dosed only once a day.
Betaxolol HCI
Betaxolol is a selective beta blocker eye medication. Selective beta blockers are typically less effective than selective ones. However, because it has fewer side effects, eye doctors can prescribe betaxolol to patients with respiratory disease such as asthma or emphysema. The doctor should be very cautious about prescribing this medication to patients with diabetes. Using a beta blocker in these people can still cause problems; the clinician usually will only select a beta blocker if no other alternative is effective.
Levobunolol HCI
Levobunolol is another non-selective beta blocker that can be administered one or two times a day. Because of the risks of systemic side effects, physicians should be careful went prescribing this medication to patients with respiratory problems or diabetes.
Metipranolol
Metipranolol is a non-selective beta blocker available only as a generic formulation. Its effect is similar to other non-selective beta blockers; the side effects are similar to other non-selective medications. In the book Glaucoma Medical Therapy: Principles and Management, Netland notes that metipranolol may be associated with a type of eye inflammation called granulomatous uveitis.
Carteolol HCl
Carteolol is a non-selective beta blocker that is available in the U.S. Although it is non-selective, it has been found to have less severe side effects than other non-selective beta blockers. However, as with the other non-selective medications, caution should be used in prescribing carteolol in patients with respiratory disease or diabetes.
References
- The Eye Digest: Glaucoma Treatment
- All about Vision: Glaucoma Treatment
- "Glaucoma Medical Therapy: Principles and Management"; Peter A. Netland and the American Academy of Ophthalmology; 2008.
