For many people, vision will worsen with age. And besides this normal process, some eye diseases may also develop that make it more difficult to see well, or that can even lead to blindness. One such common eye disease is Glaucoma. It is estimated that in the industrialized world about 1 to 2 out of 100 people over the age of 40 years have Glaucoma.
You can find more information on this topic in our feature.
What is Glaucoma?
The term “Glaucoma” covers a number of different eye conditions, all of which involve damage to the optic nerve. This damage leads to the field of vision having ever larger gaps, which mostly remain unnoticed at first. Your field of vision is the range of what you can see when your eyes are looking straight ahead. In advanced stages, your ability to see things sharply (visual acuity) also gets worse. One common cause is that there is too much pressure inside the eye. This pressure is called intraocular pressure. Intraocular pressure is caused by a fluid in the chambers of the eye between the cornea and the lens. This fluid is called aqueous humor and is produced by the eye itself. It flows continuously from the back (posterior) chamber to the front (anterior) chamber and then back out through a very thin tube (Schlemm’s canal). This cycle helps to maintain constant pressure in a healthy eye. The aqueous humor also provides nutrients to the cornea, the iris and the lens.
If the aqueous humor is prevented from draining properly, it starts to collect and pressure within the eye builds up. This presses against the optic nerve and there is a risk that nerve cells die. Whether the increased intraocular pressure does cause damage depends on, among other things, how well the optic nerve can resist this pressure: only some people with high intraocular pressure have an optic nerve that is susceptible to damage. Intraocular pressure is measured in mm Hg (millimeters of mercury), the same unit used for blood pressure. Readings between 10 and 21 mm Hg are considered normal.
Someone who has Glaucoma does not always have above-average intraocular pressure. About 40 out of 100 people who have Glaucoma do not have high intraocular pressure, but they do have damage to the optic nerve. It might be that normal pressure is already too high for these people. Another possible cause might be poor circulation of blood to the optic nerve. In this case, not enough oxygen and nutrients reach the nerve cells.
What different forms of Glaucoma are there?
The most common form of Glaucoma is primary open-angle Glaucoma. It progresses slowly, and damage to the optic nerve will not cause visual disturbance until many years later. One of the main risk factors for primary open-angle Glaucoma is high intraocular pressure. But age (people over 50 are more likely to develop it), family history, severe nearsightedness and circulation problems are all factors that can also increase risk. And people with dark skin are also more likely to develop Glaucoma. One special type of Glaucoma is called normal-tension Glaucoma: in this kind of Glaucoma the optic nerve is damaged even though intraocular pressure is normal.
Angle-closure Glaucoma (acute Glaucoma attack) is less common. It is caused by an acute blockage of the outflow of aqueous humor, whereby intraocular pressure rises steeply. Typical symptoms are acute visual disturbance, reddening of the eye, intense pain in the head and eye, or nausea. Angle-closure Glaucoma must be treated quickly to avoid any damage to the optic nerve.
Glaucoma may also result from an inflammation, injury or vascular disease. If this is the case, it is called secondary Glaucoma. In very rare cases, babies are born with Glaucoma.
This fact sheet is concerned only with primary open-angle Glaucoma.
How will this condition affect me?
Damage to the optic nerve causes the field of vision to become progressively impaired over the years, and can even eventually cause blindness. At first, people with Glaucoma can no longer see certain areas within their field of vision, or can only see them to a limited degree. Blind spots appear most often near the point of sharpest vision, but also outwards to the edges of the field of vision. These blind spots can make it increasingly difficult to get around in day-to-day life. When looking straight ahead, for example while driving, it is possible to have a clear view of the street, but people and objects to the right and left on the sidewalks will be indistinct. Adjusting to different amounts of light may also be difficult, like stepping into the light from a darkened room, or it can be hard to judge obstacles like steps or the curb. Because central vision is not affected from the start, these impairments are often not readily apparent.
Damage to the optic nerve is irreversible. By the time the first symptoms appear, this damage is usually already quite extensive. Glaucoma usually develops gradually, but can sometimes progress very rapidly as well. The blind spots may continue to spread over time, until it is only possible to see the very center of the visual field. Some people go completely blind – it is estimated that about 1,100 people go blind due to Glaucoma (all forms) in Germany every year.
How is Glaucoma diagnosed?
No longer being able to see certain parts of the field of vision or only seeing them as blurred may be a sign of Glaucoma. But an eye doctor can diagnose Glaucoma even before the first symptoms become noticeable.
Your eye doctor will first ask about any existing symptoms and then examine the eye. A special instrument called an ophthalmoscope is used to check the inside of the eye to spot possible damage to the optic nerve. Intraocular pressure is also measured, usually with a technique called applanation tonometry. The eye is first numbed using a drop of liquid. Then the doctor sets a small probe on the cornea to measure the pressure inside the eye.
If Glaucoma is suspected, your eye doctor will also measure your field of vision. This is done to see whether particular parts of your field of vision have been affected and whether you already have blind spots.
Screening
To diagnose high intraocular pressure or Glaucoma early on, many eye doctors offer screening exams that must be paid for out-of-pocket in Germany because they are not covered by statutory health insurance funds. Screenings involve checking the optic nerve, measuring intraocular pressure and examining the eye with a slit lamp. If there is good reason for suspecting Glaucoma, or if certain risk factors do exist, the statutory health insurance funds in Germany will pay for the screenings. Not enough research has been done to tell whether a general screening is a good idea for particular age or risk groups. You can read more about this in our research summary on Glaucoma screening.
How can Glaucoma be treated?
Glaucoma can be treated with medication (eye drops), laser therapy or surgery. This treatment aims to lower intraocular pressure, thereby reducing the risk of impaired vision or blindness. It is estimated that 4 to 20 out of 100 people with high intraocular pressure will have loss of vision within five years. The risk will depend on different things like the amount of intraocular pressure, the thickness of the cornea and a person’s age. People with very high intraocular pressure run a substantially higher risk than people whose intraocular pressure is only slightly elevated.
Lowering high intraocular pressure can help to delay or stop the gradual progression of loss of vision. Glaucoma cannot be cured, however, because existing damage to the optic nerve cannot be reversed. Eye drops are used both as prevention and treatment to lower the intraocular pressure. Depending on the specific product, you use them either once or several times a day. If eye drops are not enough, or if they are not well tolerated, surgery can be an option for permanently lowering intraocular pressure to certain target levels.
What benefit does the prevention and treatment of Glaucoma have?
This medication can be used to prevent Glaucoma if intraocular pressure is too high, but there is no damage to the optic nerve or visual field impairment. Trials show that people who had high intraocular pressure, but who had not yet had Glaucoma, were less likely to develop visual field impairment if they took eye drops:
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Vision got worse in 5 out of 100 people who used eye drops after about five years.
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In contrast, vision got worse in 8 out of 100 people who did not take medicine or who only had a fake treatment.
Whether it makes sense to have preventative treatment also depends on possible risk factors. If there is no damage to your eyes and you only have slightly high intraocular pressure and no additional risk factors, your eye doctor may advise you to not have any treatment. But if your values are very high and you also have close relatives with Glaucoma, odds are much higher that you will benefit from treatment.
If Glaucoma has already developed, it is also important to keep intraocular pressure down by using medication in order to minimize loss of sight as much as possible. Medication is also used to treat people who have Glaucoma, but whose intraocular pressure is normal. Sometimes surgery may also help to lower the intraocular pressure. A trial looked at how newly diagnosed Glaucoma develops with and without treatment. The participants were divided into two groups: One group had laser therapy and took beta blockers. The other group did not have any treatment. The results after two years:
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Glaucoma advanced in 30 out of 100 people in the treatment group.
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Glaucoma advanced in 49 out of 100 people who did not receive treatment.
In other words, treatment stopped Glaucoma from getting worse in 19 out of 100 participants over two years. Yet even with therapy, vision and impairment of the visual field may still get worse.
Which medications are used?
These medications can be used for treatment:
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Beta blockers reduce production of aqueous humor. Beta blockers have been in use for quite some time and are often prescribed as first-line therapy.
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Cholinergic agents increase outflow of aqueous humor. Cholinergic agents have also been in use for treating Glaucoma for a long time.
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Prostaglandins increase outflow of aqueous humor and are often prescribed as first-line therapy. They have only been on the German market since the late 1990s.
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Alpha-agonists lower production of aqueous humor and increase its outflow.
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Carbonic anhydrase inhibitors lower production of aqueous humor.
Which medication is best in a particular case depends on different factors. The extent of optic nerve damage, the amount of intraocular pressure, possible adverse effects, age and other factors will influence which medication suits you best. If intraocular pressure cannot be lowered enough by using one medication or there are side effects, it is also possible to switch medications.
It is a subject of debate whether neuroprotective drugs could be used as an alternative treatment. These drugs aim to protect the cells in the retina and in the optic nerve. But there has not yet been any research showing the benefit of this medication for people who have Glaucoma.
Adverse effects
These medications can have various adverse effects. All of them can irritate the eye and cause itching and redness, for example. Some, such as the beta blockers, can affect the cardiovascular (heart and circulation) system and make breathing difficult. Closing your eyes for three minutes after using the eye drops is recommended to lower the probability of adverse effects. You can also lightly press the inside corners of your eyes with your fingers. Both of these things are done to make sure that the eye drops act on the eye, and do not flow down into your nose and throat where they can be absorbed into the body through mucous membranes.
What problems can occur during use?
Many people have a difficult time using eye drops up to several times a day for many years at a time. Some find it inconvenient to have to search for a quiet spot at work or while going somewhere so that they can take the eye drops. Others often forget to use the medicine. Some people have the feeling that the eye drops are not helping much anyway, so they do not use them consistently. Because things do not get worse immediately if you forget to take the medication once, quite some time may go by before you realize that you have not been taking the medicine on a regular basis. And its benefit becomes apparent only after a longer time period, so it will not be noticeable immediately. You can read more about strategies that may help you to take medicine over longer periods of time in our fact sheet on managing medicines for long-term conditions.
Keeping regular appointments with your eye doctor can help you remember to take your eye drops. It might also be helpful to take the medication at fixed times or in connection with daily rituals (for example at breakfast, dinner, or bedtime). Some people say that it helps them to stay motivated knowing that the medication can help them to keep their sight over the long term. Others work out a plan together with their doctor so that they only have to take the drops three times a day instead of six, for example. Then they do not have to remember so often.
Some people mostly have trouble combining taking the eye drops with their daily routine. If you have never taken eye drops before, it is not always that easy to handle them. Older people also often have trouble using eye drops on their own. If you are not sure that you are using the drops correctly, it is a good idea to go to your doctor’s office and have them carefully explain what you need to do. Self-help groups can also provide support here: many offer assistance in proper use of eye drops. This illustration demonstrates the best way to apply eye drops.
Can surgery, laser therapy or acupuncture help?
Glaucoma can also be treated with lasers or surgery. These treatments are an option particularly if it has not been possible to keep intraocular pressure under control by using just medicine or if the drops are not well tolerated.
Acupuncture is also sometimes used as complementary treatment for Glaucoma. The acupuncture needles are not used directly on the eye, but between the eyebrows or at other points on the body. There is not yet any scientific proof of a benefit from this treatment, however.
Trabeculectomy
Glaucoma surgery is done to lower intraocular pressure permanently. The most common procedure is called trabeculectomy, which involves cutting out a bit of the sclera (the white outer layer of the eye) and the iris in order to improve outflow of aqueous humor, thereby lowering pressure inside the eye. Possible adverse effects of this type of surgery include vision problems immediately after surgery, scarring and, over the long term, cataracts.
Laser therapy
Intraocular pressure can also be lowered by using lasers, but usually not by as much as is possible in surgery. In early stages of Glaucoma, laser therapy can improve the outflow of aqueous humor. It is also possible as supplementary therapy to eye drop treatment. In later stages a laser can sometimes be used to destroy part of the tissue producing the aqueous humor, which will lower intraocular pressure. Laser therapy can cause red or dry eyes and blurry vision immediately after treatment.
How can I cope with losing my vision and fear of sight loss?
If an examination finds high intraocular pressure, many people will feel quite nervous about it, even though their vision is still perfectly fine. Just knowing that you have high intraocular pressure, and therefore a higher risk of developing Glaucoma, may cause you to worry if you have even the slightest trouble with your vision, although it most likely has nothing to do with Glaucoma. Frequently, people with Glaucoma are very afraid to go blind at some point. Especially at the start, many people want to have detailed information on their treatment and about what implications the diagnosis has for their own life.
People whose vision continues to worsen despite treatment find themselves in a very different situation. Glaucoma-report.974.en.html" ref="pagearea=body&targetsite=external&targetcat=link&targettype=uri" style="margin: 0px; padding: 0px; border: 0px; font-size: 13px; font: inherit; vertical-align: baseline; color: rgb(100, 42, 143); ">People with Glaucoma report
This means that, sooner or later, changing your daily activities to suit your new situation is inevitable. For example, you may have to rearrange things in or around your home to help give you a better orientation. It may also affect your professional life. And you might not be able to do such everyday things as sports, shopping or reading the way you used to do them. It may then be a good idea to get support and find out about different aids to make your day-to-day life a bit easier. The first place to go might be your doctor or health insurer. People who have Glaucoma also say that it helps them to get information about the condition and ways of coping with it or to talk with others who also have Glaucoma, for example in a self-help group or on an internet forum.
It is difficult for many people to realize the point at which this condition makes it impossible to drive a car safely. At first, people with Glaucoma often start making changes to their driving habits and stop driving at night or only stay on familiar streets. It is important for family and friends to be aware of this and help pay attention to when these limitations are too great, and the person possibly becomes a danger to him or herself and others. German law prohibits driving once impairment to the visual field becomes too great. Your eye doctor can give you more concrete information and advice.
It is often not easy to deal with becoming more dependent on help from others due to problems with your vision. Giving up control over some things and trusting other people might become necessary, however.
Talking over your worries and fears with family and friends early on can be a great relief. Together you can develop strategies for dealing with how your condition develops. Having people who are there for you and understand and support you can really make things easier in any circumstances – and this is especially true if you are dealing with a difficult health condition and want to continue to stay as active as you can.
Author: Institute for Quality and Efficiency in Health Care (IQWiG)
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