Glaucoma is an eye condition usually caused by increased pressure inside the eyeball, which, if left untreated, can cause irreversible damage to the optic nerve—leading to vision loss, even blindness. It affects 2.4 million Americans older than age 40, but only half of them know they have it.
Reason: Early-stage glaucoma has no detectable symptoms and can be discovered only through an eye exam.
Vital: Get an eye exam from an ophthalmologist every two or three years if you are age 61 or older. If glaucoma is detected and treated early, vision loss can usually be prevented. What you need to know…
One of the biggest advances in recent years is the development of scanning devices that measure the amount of healthy optic nerve tissue. If glaucoma is suspected, these can be used to evaluate how much nerve damage has occurred as well as allow doctors to monitor how well glaucoma treatments are working over time. Three types of scans…
- Heidleberg retina tomograph creates a high-resolution, 3-D image of the optic nerve.
- Optical coherence tomograph obtains high-resolution cross-sectional images and creates a 3-D image of the retina and optic nerve.
- GDx nerve fiber analyzer uses filtered light to measure nerve tissue in the retina.
All three types of scans are equally effective and can be done in-office. If your ophthalmologist doesn't have access to a scanning device, ask him/her to refer you to a clinic that does.
Since vision loss due to optic nerve damage is irreversible, the key in treating glaucoma is early detection and intervention. The three approaches to treatment—medications, laser procedures and surgery-all significantly lower intraocular pressure (IOP) and thereby protect the optic nerve by reducing fluid levels in the eye…
Eyedrop medications are usually the first-line treatment for glaucoma. Four types…
- Prostaglandins—travoprost (Travatan), bimatoprost (Lumigan) and latanoprost (Xalatan). Typically the first drugs tried, they don't cure glaucoma, so they must be used indefinitely. Prostaglandins increase fluid drainage in the eye, usually lowering IOP 25% to 30%. Possible side effects include gradual change in eye color due to increased brown pigment in the iris, and stinging, redness, itching or burning of the eyes.
If a prostaglandin isn't fully effective, your doctor may try any of the following drugs, either alone or in combination with a prostaglandin.
- Beta blockers—timolol (Betimol, Istalol, Timoptic), betaxolol (Betoptic), levobunolol (Betagan) and metipranolol Optipranolol)-reduce TOP by reducing fluid production and slightly increasing the rate of flow through and out of the eye. They're as effective as prostaglandins at lowering IOP but can result in more serious side effects, including low blood pressure, reduced pulse rate, fatigue and shortness of breath.
- Alpha 2 agonists—apraclonidine (Iopidine) and brimonidine tartrate (Alphagan)decrease fluid production in the eye. While not quite as effective as prostaglandins or beta blockers, their potential side effects are less bothersome, compared with beta blockers, for many patients. These include burning or stinging upon administration of the drops, fatigue, headache and dry mouth.
- Carbonic anhydrase inhibitors—brinzolamide (Azopt), dorzolamide (Trusopt), acetazolamide (Diamox) and methazolamide (Neptazane)-decrease fluid production. They're available as eyedrops and in pill form. The drops are about as effective as alpha 2 agonists. The pills are somewhat stronger but have more potential side effects, including tingling or weakness in the hands and feet, upset stomach, mental fuzziness, memory problems, depression, kidney stones and frequent urination.
Once the patient's glaucoma stabilizes, treatment continues for life—or until it stops working. Checkups occur every three to six months to monitor IOP and optic nerve condition.
If medications stop working, or a patient tires of daily eyedrops, a laser surgical procedure—which takes just minutes and can be done in-office—is an option…
- Selective laser trabeculoplasty (SLT). This new technique may be a viable alternative to medications as a first-line treatment for open-angle (the angle between the cornea and the iris) glaucoma, the most common type of glaucoma in the US. SLT uses a low-level laser (which minimizes collateral tissue damage and scarring) to improve the function of the eye's drainage canals, improving fluid flow and reducing IOP, often to the point where medication is no longer needed. Some people will still need to use drops afterward. Like any surgery, SLT can cause complications, including scarring-though this risk is minor.
- Argon laser trabeculoplasty (ALT). An older technique more widely available than SLT, ALT uses a high-energy laser (which can cause tissue damage and scarring) to open the eye's drainage system. It's as effective as SLT for open-angle glaucoma, but has more scarring risk, which could result in increased eye pressure and negatively affect vision.
- Laser peripheral iridotomy is commonly used for closed-angle glaucoma, which affects mainly people of Asian descent. A laser makes a hole in the iris, removing the blockage and allowing fluid to flow out of the eye normally
If medications and laser surgery don't stop glaucoma progression, a number of effective operations are available. The most common, trabeculectomy, involves building a new drainage system from the patient's own eye tissue. This remains the gold standard in glaucoma surgery, producing significant, lasting reductions in IOP.
Problem: To prevent scarring, at the time of surgery most patients are given medications that can sometimes cause serious eye infection later on. Other complications, such as worsened cataract, severe blurring that can last several weeks and/or bleeding in the eye can occur. Also, a very slight droop in the eyelid is common.
Latest advances: New surgical techniques let patients minimize risks. One still in clinical studies involves implanting a synthetic drain in the eye. Another newer procedure entails implanting a tiny shunt made out of gold to channel eye fluid to an area where it's more easily absorbed into the bloodstream. If the shunt becomes clogged, a titanium sapphire laser-which selectively targets gold—may be used to reopen it.
Another procedure, canaloplasty, involves inserting a tube into the eye's natural drain. This doesn't require lifelong medication. It's the first operation that works on the eye's own drain, rather than creating an alternate drainage system. Results are promising, but long-term efficacy hasn't been established.
Two other promising advances, but where the long-term effects aren't yet known…
- Removing the part of the eye's drainage system that's preventing fluid flow and replacing it with a Trabecutome shunt, a device that slips into the eye drain and allows diseased tissue to be removed using electrical sparks.
- Going around the clogged section entirely using a Glaukos iStent—a tube-like device that takes fluid past the clogged portion of the eye's drain, bypassing the diseased tissue and lowering the eye pressure.