What are the risk factors of glaucoma?
Most forms of glaucoma are strongly related to advancing age, but there are many other factors leading to increased susceptibility. There is often a genetic component in many forms of open angle glaucoma. Those with a family history of the disease, as well as African-Americans, are at increased risk. There is currently much controversy about the contribution of other systemic diseases, such as high blood pressure and diabetes, to the development of glaucoma.
Studies have shown individuals who are at greater risk for glaucoma often fit into one or more of the following criteria:
- Over the age of 60
- Have a family history of the disease, especially in a parent or sibling
- Have elevated intraocular pressure
- Are African-American over the age of 40
- Have diabetes or hypertension, especially longstanding
- Are nearsighted
- Have thin corneas
Individuals who possess any of the non-age-related risk factors should have regular examinations by an ophthalmologist every year or two. Early detection is critical to prevent vision loss, especially in patients with obvious disease who do not have any symptoms. There is no way to know if someone has glaucoma by just measuring the intraocular pressure or by any vision- related symptoms an individual may be experiencing. The optic nerves in both eyes must be fully visualized, ideally with a dilated eye exam, and the peripheral visual field must be tested. Individuals in the general population should have a glaucoma evaluation every two or three years after the age of 40, and every year or two after the age of 60.
What is involved in a glaucoma evaluation?
Every year, many patients are diagnosed with glaucoma who already have moderate to very advanced glaucoma. Many of these patients could have benefited from much earlier diagnosis or more careful and precise monitoring of their risk factors. Other patients who already are known to have glaucoma can benefit from a more accurate assessment of their risk of progression of the disease over time with more advanced assessment in order to prevent further vision loss over time.
To achieve a full and accurate assessment, experienced ophthalmologists, optometrists and technical support staff perform different parts of a comprehensive glaucoma screening that consists of several different areas of testing.
In its early stages glaucoma is very difficult to diagnose and several different approaches need to be used to accurately assess whether a patient has glaucoma or more accurately assess their risk of developing the disease. All tests in glaucoma assessment are painless, non-invasive and safe.
Measurement of Intraocular Eye Pressure (IOP)
Elevated IOP is considered a major risk factor for the development of glaucoma. Studies have shown that optic nerve damage becomes more likely as IOP increases. Measurement of the corneal thickness also provides valuable information about the accuracy of the pressure measurement as well as additional information about the risk of glaucoma. Measuring intraocular pressure at different times of the day may be important in some cases.
Assessment of the optic nerve
A non-invasive slit lamp biomicroscope is used to determine whether or not there are changes in the optic nerve consistent with the diagnosis of glaucoma. Stereo photographic or advanced imaging techniques of the nerve fiber layer of the optic nerve may also be used such as Optical Coherence Tomography. These instruments may show damage from glaucoma at a much earlier stage than can be detected by other methods and may also show progression before other methods can.
Evaluation of a patient’s peripheral visual field
Glaucomatous damage produces characteristic defects in the visual field or peripheral vision, but with standard visual filed testing glaucoma damage may not become evident until significant optic nerve damage occurs. At Intermountain Eye Centers we employ several different advanced techniques, including Short Wavelength Automated Perimetry and FDT perimetry, which sometimes can detect glaucomatous visual field damage far earlier than more standard tests.
Depending on the situation, the diagnostic tests performed during a glaucoma evaluation will be individualized for each patient based on their exact needs. Usually one of the glaucoma specialists will carefully go over the results of all these tests, integrating them into a complete assessment for each patient to arrive at an appropriate plan of treatment.
What are the treatments for glaucoma?
Glaucoma treatment seeks to decrease intraocular pressure or use other methods to prevent damage to the optic nerve. Currently, lowering intraocular pressure is the only proven method to treat glaucoma, but several other different strategies, including neuroprotective treatment, are being researched and developed. Different types of glaucoma require different therapies to prevent further damage to the eye’s structures. At the beginning of treatment, the ophthalmologist will generally recommend medication or a combination of medications or laser treatment to lower the intraocular pressure. Individualized treatment is very important in treating any type of glaucoma.
Eye drops (or a combination of eye drops and pills) can be used to reduce intraocular pressure. Several different classes of glaucoma medications are currently available to lower eye pressure. These include beta-blockers, prostaglandin analogues, alpha-adrenergic agonists, miotics, and oral and topical carbonic anhydrase inhibitors. These medications work by either reducing the rate at which fluid in the eye is produced or increase the outflow of fluid from the eye. Although some categories of medications are best as first-line treatment in most situations, the exact type of eye drops used requires careful assessment of a patient’s individual needs.
Another option is laser treatment to open the drainage angle and reduce intraocular pressure. For angle closure glaucoma the ophthalmologist will likely recommend a laser iridotomy. For open angle glaucoma trabeculoplasty may be recommended. There are two types of trabeculoplasty available: the original type, called Argon Laser Trabeculoplasty (ALT), and a newer, more advanced type called Selective Laser Trabeculoplasty (SLT). Both of these technologies are available at Intermountain Eye Centers. Sometimes in complex cases a different type of laser treatment to reduce intraocular pressure called cyclophotocoagulation (TCPC) will be recommended. Usually these treatments are office procedures and are relatively painless and safe. A newer form of this type of procedure using micro-pulse laser technology is now being offered to more patients than the previous TCPC treatments.
Surgery to create a new passage for fluid drainage. Surgery is usually reserved for cases that cannot be controlled by medication or appropriate laser treatment but that has recently changed. There are several different surgical approaches including trabeculectomy, tube shunt implants, and canaloplasty surgery. Each patient’s situation is unique and if a patient requires glaucoma surgery careful individual counseling about the different options, as well as risks and benefits will be fully discussed.
Minimally invasive glaucoma surgery (MIGS) is a newer technique to lower the eye pressure using very small drainage implants. Glaucoma specialists at IEC have been in the forefront of using these safer techniques for glaucoma surgery. Very few other locations in the United States offer as many different surgical options as the glaucoma service at the Intermountain Eye Centers.
IEC is currently involved in two surgical glaucoma clinical trials. One involves a MIGS-type implant that may be an improvement on trabeculectomy. And the second involves implanting IOP-lowering medications in the eye as an alternative to eye drops for medical treatment of glaucoma.