Expert

Five Common Myths About Glaucoma

University of California, San Francisco, UCSF Medical Center
Graphic of two arrows; one pointing to myths and the other pointing ot facts

Learn the facts concerning five common glaucoma myths.

MYTH: If you have 20/20 vision and no symptoms, you won’t develop glaucoma.

FACT: Glaucoma is often called the “silent thief of sight” because people will not notice symptoms until the glaucoma is moderate or advanced. The definition of early glaucoma is based on the fact that you do not even need to have problems with your peripheral (side) vision, but is rather determined by your eye doctor's observation of the appearance of your optic nerve. Therefore, even though you will not have symptoms in early glaucoma, if untreated, vision will slowly deteriorate. Another reason that patients do not notice changes in their vision, is that one eye can compensate for any defects in the other eye’s peripheral vision. Sadly, it is possible that people can have advanced peripheral vision loss without realizing it. Furthermore, it is known that the later the disease is diagnosed and treated, the worse the long-term outcome. This observation has been borne out in numerous clinical studies and emphasizes the importance of identifying and treating glaucoma early.

MYTH: Glaucoma only affects the elderly.

FACT: While it is true that the risk of having glaucoma increases as we get older, and that the majority of open-angle glaucoma is age-related, this eye disease can affect people of all ages, even newborns. For example, some babies have congenital glaucoma, while other children have other eye diseases that lead to secondary glaucoma. The same is true for adults—one can have an eye condition, for example uveitis, that results in a secondary glaucoma. There are also other types of glaucoma that often manifest in patients between ages 20 and 50, such as pigmentary glaucoma. However, for the majority of open-angle glaucoma cases in the United States, the prevalence increases in older age groups. Persons ages 70 and older are at 3- to 8-fold greater risk of having primary open-angle glaucoma compared to persons in their 40s.

MYTH: Glaucoma only occurs if you have elevated eye pressure.

FACT: While it is true that elevated eye pressure is a major risk factor (and can be causative) of glaucoma, some people with elevated eye pressure do not develop this eye disease. It is also possible to have severe glaucoma with so-called “normal” eye pressures. People in the first group have ocular hypertension and people in the latter group have normal-tension glaucoma (NTG).

Ocular hypertension occurs when there are documented high eye pressures but no evidence of optic nerve or field of vision damage. However, depending on risk factors and the specific patient situation, some eye doctors will recommend treating the elevated eye pressures. In fact, in one well-designed randomized controlled trial, called the Ocular Hypertension Treatment Study (OHTS), people with ocular hypertension who were treated with eye pressure lowering medications, reduced their risk of developing glaucoma by more than 50 percent. What is important to note, however, is that a relatively small percentage, about 9.5 percent of untreated patients, developed glaucoma during the 5 years of the study, compared to 4.4 percent of those who were treated. 

Shifting our attention to normal tension glaucoma, there are some eye doctors who do not like this term because it implies that there is such a thing as a “normal” eye pressure. But defining NTG by eye pressure alone is really a statistical phenomenon, meaning that when eye doctors examine eye pressures across a large population, they know that having a pressure greater than 21 mmHg (millimeters of mercury) should occur in less than 5 percent of the population. We do not know if those patients with a pressure lower than 21 mmHg really have NTG as a separate and distinct disease from open-angle glaucoma, and some think that it is just part of the continuum of open-angle glaucoma. Semantics aside, it is very apparent that one can develop glaucoma even if one’s eye pressure never exceeds 21 mmHg. The Collaborative Normal Tension Glaucoma Study demonstrated that lowering eye pressure in patients with NTG slowed progression of the disease.

MYTH: There is no reason undergo treatment for glaucoma if there are no symptoms, especially since there is not a cure for the disease.  

FACT: It is true that most forms of glaucoma don’t produce symptoms, and many of the treatments have some side effects or have an impact on quality of life. While there is currently no cure for glaucoma, there are, however, effective medications, lasers, and surgeries to help slow the disease. The eye doctor’s job is to slow the disease to minimize the chances of developing visual field damage that impacts the ability to function. Certainly, there are side effects of treatments, but you, along with your eye doctor, can work together to find a suitable solution to minimize these unwanted effects. Furthermore, while treatment is not a guarantee that the glaucoma will not worsen (there are situations where the eye pressure is well-controlled, but glaucoma can still progress), it is known that if patients with glaucoma are left untreated, many will proceed to lose vision.

MYTH: Glaucoma is inherited, and since no one in my family has glaucoma, I won’t get the disease.

FACT: While it is true that certain forms of glaucoma are inherited, and that a family history of glaucoma is a risk factor, there are many glaucoma patients who are the only ones in their families who are diagnosed with this eye disease. It is also possible that there does not appear to be a strong family history because not all family members have been appropriately examined. All patients with glaucoma should share their diagnosis with their family members and ask them to have a dilated eye examination. Indeed, the American Academy of Ophthalmology recommends that all adults with no signs of eye disease or risk factors have a baseline dilated eye examination at age 40. This is because many early signs of disease and changes in vision can start to occur around this age. And given that glaucoma is symptomless in most cases, it is even more important that family members of patients with glaucoma have their eyes thoroughly examined.


Resources:

Glaucoma: Essential Facts (Publication)

This content was first posted on: March 7, 2015

The information provided here is a public service of the BrightFocus Foundation and should not in any way substitute for personalized advice of a qualified healthcare professional; it is not intended to constitute medical advice. Please consult your physician for personalized medical advice. BrightFocus Foundation does not endorse any medical product, therapy, or resources mentioned or listed in this article. All medications and supplements should only be taken under medical supervision. Also, although we make every effort to keep the medical information on our website updated, we cannot guarantee that the posted information reflects the most up-to-date research.

These articles do not imply an endorsement of BrightFocus by the author or their institution, nor do they imply an endorsement of the institution or author by BrightFocus.

Some of the content may be adapted from other sources, which will be clearly identified within the article.

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