Glaucoma

Jan 21, 2025

by Mette Wotkjær

Glaucoma is a serious eye disease that can lead to permanent vision loss if not detected and treated in time. It is one of the most common causes of blindness worldwide, affecting millions of people each year. Read on to learn what glaucoma is, how it is diagnosed and treated, and what you can do to reduce your risk of developing it.

What is glaucoma?

Glaucoma is an eye disease in which the optic nerve (which connects the eye and the brain) is permanently damaged by elevated pressure in the eye. This pressure is due to a blockage of the normal fluid drainage from the eye. Without treatment, the eye disease can lead to 'tunnel vision' or blindness.

What does glaucoma feel like?

Glaucoma can develop slowly and without obvious symptoms at first, which is why the eye disease is called 'the silent thief of sight'. In the acute type of glaucoma, there is a sudden blockage in the eye's drainage channels, which significantly increases the pressure in the eye. Symptoms will include reduced vision and rainbow vision, pain, severe headache, and possibly vomiting. If you experience sudden eye pain or rapid vision loss, seek immediate medical attention.

What causes glaucoma?

Glaucoma primarily involves permanent damage to the optic nerve, often due to elevated pressure in the eye (intraocular pressure). If the optic nerve is damaged, the eye's light impressions cannot be transported and converted into images, affecting vision. However, there are other risk factors that can influence the development of the disease:

Elevated intraocular pressure: The eye's internal fluid (aqueous humor) drains through an outflow system in the eye (trabecular meshwork). If drainage is impaired, the pressure in the eye increases, which can damage the optic nerve over time. However, not everyone with elevated intraocular pressure develops glaucoma, and some develop glaucoma without elevated pressure.
Genetics: Heredity plays a significant role. If there is a family history of glaucoma, the risk of developing it is higher.
Age: The risk of glaucoma increases with age, especially after 60.
Blood supply: Poor blood circulation to the optic nerve can make it more vulnerable to damage.
Diseases: Certain diseases and conditions can increase the risk of glaucoma, such as diabetes, high blood pressure, and cardiovascular diseases. Eye injuries, severe infections, or inflammation can also lead to glaucoma.
Medication use: Long-term use of corticosteroids (both eye drops and systemic steroids) can increase the risk of developing glaucoma.
Eye injuries: Previous eye injuries or abnormal structures in the eye's drainage system can lead to glaucoma.

What are the first signs of glaucoma?

Glaucoma often develops slowly and without obvious symptoms at first, which is why it is known as 'the silent thief of sight'. Regular eye exams are crucial for early detection. If you experience sudden eye pain or rapid vision loss, seek immediate medical attention. Also, keep an eye out for symptoms such as:

Constricted field of vision: An early sign of glaucoma is that you begin to lose your peripheral vision. Here, you will gradually lose the ability to see things in the outer edges of your field of vision (peripheral vision), while central vision is sharp at first. This is often called 'tunnel vision' as it feels like looking through a 'tunnel'. Constricted vision can be difficult to notice as it often happens gradually.
Blurred vision: In some cases, glaucoma can lead to blurred or distorted vision, often due to increased eye pressure or damage to the optic nerve. You will notice a reduced ability to see details and things clearly, which can range from mild blurring to a feeling of looking through a foggy or dirty glass. Light can appear sharp or uncomfortable, and judging distances can be a challenge.
Redness in the eye: In some cases, especially with acute glaucoma (where eye pressure rises rapidly), the eye can become red and painful. This can be associated with other symptoms such as nausea, vomiting, and headache.
Rainbow colors around lights: Most often seen in acute angle-closure glaucoma (a rare and severe form of glaucoma), where you will see rainbow-colored circles or halos around light sources, such as streetlights, car headlights, or lights in the home. If you experience rainbow colors around lights along with other symptoms of acute glaucoma, seek immediate help from an ophthalmologist or emergency room.
Visual disturbances in dim light: Some people with glaucoma notice that they have more difficulty seeing in the dark or dim light or at night.
Headache or nausea: In rare cases, especially with acute glaucoma, you may experience headache, nausea, vomiting, and visual disturbances, which may be signs of a sudden increase in eye pressure.
Eye pain: Sharp or throbbing pain in one eye, often accompanied by a feeling of pressure. The pain can radiate to the rest of the head and is often confused with migraine or tension headaches. Some experience nausea or vomiting as a result of the severely elevated eye pressure.

If you suspect you have glaucoma, it is important to contact an ophthalmologist as soon as possible for a thorough eye examination. The ophthalmologist will be able to assess the eye pressure, visual field, and optic nerve to determine or rule out glaucoma. Early treatment of glaucoma can help preserve your vision and prevent.

How many types of glaucoma are there?

There are many types of glaucoma, each with different causes, symptoms, and treatment methods. The main types are:

Primary open-angle glaucoma: The most common type, caused by a slow blockage in the eye's drainage channels, which increases pressure in the eye. Develops slowly and often without symptoms at first.
Acute angle-closure glaucoma: A rarer, but acute and painful form. Occurs when the eye's drainage system is suddenly blocked, leading to a rapid increase in pressure. Severe symptoms such as pain, red eye, nausea, and rainbow colors around lights. Requires immediate treatment.
Secondary glaucoma: Occurs as a result of another disease, injury, or condition such as diabetes, eye injuries, or inflammation.
Congenital glaucoma: A rare congenital condition where the eye's drainage system does not develop correctly from the start.
Childhood glaucoma or congenital glaucoma: A rare type of glaucoma seen in infants or young children. Caused by a congenital defect in the eye's drainage system. Symptoms may include large, cloudy corneas, light sensitivity, and watery eyes.
Normal-tension glaucoma: Intraocular pressure is within the normal range, but the optic nerve is still damaged. The cause of normal-tension glaucoma is still unknown, but reduced blood flow to the optic nerve may play a role.
Pigmentary glaucoma: Caused by pigment released from the iris blocking the drainage channels in the eye. Often seen in younger adults and can be hereditary.
Exfoliation glaucoma (pseudoexfoliation): Occurs due to an accumulation of protein-like deposits in the eye. The deposits can clog the eye's drainage system and lead to elevated intraocular pressure, damaging the optic nerve.
Neovascular glaucoma: Caused by abnormal growth of blood vessels in the eye's drainage system, often occurring due to diabetes or retinal diseases.

Can you prevent glaucoma?

Prevention begins with awareness. Although glaucoma cannot always be prevented, because certain factors such as age and genetics play a significant role, there are several ways to reduce the risk of the disease or slow its progression if detected early. Here are some effective measures:

Monitor symptoms: Be aware of signs such as blurred vision, eye pain, or vision loss, and seek immediate medical attention if they occur.
Eye exams: Early diagnosis is the best way to prevent vision loss. People over 40 or in high-risk groups should have their eye pressure and optic nerve checked regularly by an optician or ophthalmologist.
Know your genetics: If glaucoma runs in your family, it's important to inform your ophthalmologist, as this can increase your risk.
Avoid eye injuries: Wear protective eyewear during sports activities or work where there is a risk of eye injury, as trauma can lead to secondary glaucoma.
Eat healthy: Foods rich in antioxidants, vitamins, and minerals can boost eye health, such as leafy greens and carrots.
Exercise regularly: Exercise can help reduce eye pressure, especially if you are at risk.
Avoid smoking: Smoking can worsen blood circulation, including to the eyes.
Control chronic diseases: Keep diseases such as diabetes and high blood pressure under control, as they can contribute to eye damage.
Limit the use of certain medications: Long-term use of corticosteroids, especially eye drops, can increase the risk. Consult your doctor if you rely on these medications.
Wear sunglasses: Avoid exposing your eyes to bright light by wearing sunglasses

How is glaucoma detected?

Glaucoma is often detected through a thorough eye examination by an optician or ophthalmologist. Since the disease often develops slowly and without obvious symptoms in its early stages, regular examinations are crucial for early detection and treatment. Here are the main methods for detecting glaucoma:

Measurement of intraocular pressure (tonometry): Glaucoma is often associated with elevated pressure in the eye, which can damage the optic nerve.
Visual field test: This test assesses your peripheral vision to detect any areas where vision is impaired. Vision loss often begins in the outer edges of the visual field.
Optic nerve examination (fundoscopy): The ophthalmologist uses a microscope or a special lens to examine the optic nerve at the back of the eye. A damaged optic nerve can indicate glaucoma.
Measurement of corneal thickness (pachymetry): The thickness of the cornea can affect the measurement of intraocular pressure and your risk of glaucoma.
Angle evaluation (gonioscopy): An examination that assesses the angle between the iris and the cornea, where fluid normally drains. This is used to determine if you have open-angle or angle-closure glaucoma.
Optical coherence tomography (OCT): An advanced imaging technology that creates detailed images of the optic nerve and retina. It can show early damage before it causes noticeable symptoms.

Can you have surgery for glaucoma?

Yes, you can have surgery for glaucoma if necessary, especially if the disease cannot be adequately controlled with medication or eye drops. The purpose of glaucoma surgery is to lower intraocular pressure to prevent further damage to the optic nerve. There are several different surgical methods that can be used, depending on the type of glaucoma and how advanced the disease is. Here are the most common treatments for glaucoma:

Laser treatment: Here, a laser is used to improve the drainage of aqueous humor in the eye, which can help lower intraocular pressure.
Microsurgery: This operation creates a new drainage channel in the eye to help fluid drain properly and thus reduce intraocular pressure.
Angle surgeries: These operations are used to open the blockage that prevents fluid from draining properly in cases of angle-closure glaucoma.

When is surgery necessary for glaucoma?

Surgical treatment for glaucoma is necessary when…
…intraocular pressure cannot be controlled with medication.
…there are side effects or complications with the medication used to treat glaucoma.
…the disease is advanced and there is a risk of vision loss.

Is surgery the only option for glaucoma?

Surgery is not necessarily the first treatment option. Most people with glaucoma can effectively control the disease with medication (eye drops), which lowers the pressure in the eye. In some cases, however, surgery may be necessary if medication is insufficient or if there are complications.

Can you go too long with glaucoma?

Yes, it is possible to go too long with glaucoma, especially since the disease often has no clear symptoms at first and develops slowly. If the disease is not detected and treated in time, the pressure will remain high, and the optic nerve will be damaged more and more, which can lead to chronic vision loss.

What is the difference between glaucoma and cataracts?

Glaucoma and cataracts are both eye disorders, but they are two different eye diseases. Cataracts can usually be treated with surgery, while glaucoma is more serious as it can damage the optic nerve and lead to blindness if not treated in time.

Briefly about glaucoma: Glaucoma is a condition where there is a slow destruction of the optic nerve, often due to elevated pressure in the eye. This damage can lead to gradual vision loss and, in the worst case, blindness if not treated. In Denmark, approximately 100,000 people suffer from glaucoma, but only half are diagnosed. To preserve vision, it is important to receive treatment, which primarily involves eye drops.

Briefly about cataracts: Cataracts occur when the eye's natural lens becomes cloudy. This cloudiness prevents light from passing through the lens, causing blurred or reduced vision. Cataracts can be treated with surgery, where the old lens is replaced with an artificial lens. Cataracts typically develop with age. 50% of people over 80 have developed cataracts, and approximately 30-40% in the Western world undergo cataract surgery. Read more about cataracts and learn more about the eye disease.

Is glaucoma hereditary?

Yes, glaucoma can be hereditary, and family history plays a significant role in the risk of developing the disease. If one or more close family members have glaucoma, it increases your risk of developing the disease. We recommend that you have regular eye examinations, even if you have no symptoms.

Reading glasses and glaucoma

If you have glaucoma and have gotten older, it is also possible that you have developed presbyopia (age-related farsightedness), which may mean you need reading glasses to see clearly at close range. Presbyopia is a natural age-related phenomenon that starts around 40-45 years of age. The lens in the eye loses its flexibility, making it more difficult to focus on objects and texts up close. This is independent of glaucoma. Read more about presbyopia and learn more about whether you need reading glasses.

When should you seek help?

Glaucoma is a serious eye disease that can lead to chronic vision loss if not detected and treated in time. Since the disease often develops slowly and without symptoms at first, it is important to be aware of when you should seek help. Although glaucoma is often asymptomatic in its early stages, keep an eye out for symptoms such as:

Tunnel vision: When your field of vision gradually narrows, especially in the peripheral areas.
Blurred vision: If you notice that your vision is blurred or unclear, it could be a sign.
Eye pain: Sudden, severe pain in the eye can be a sign of acute glaucoma.
Rainbow colors around light sources: If you see halos or rainbow colors around lights.
Headache and nausea: If you have a headache that causes eye pain, it could be a sign of acute glaucoma, which requires immediate help.

Have your eyes examined regularly

Many people with glaucoma experience no symptoms until their vision is already very poor. Therefore, you should have regular eye exams if you are over 40, or have a family history of glaucoma, nearsightedness, or diabetes, you should have your eye pressure and visual field checked at least every two years. If you are over 60, we recommend that you have your eyes examined annually by an optician or ophthalmologist.

Facts about glaucoma

Glaucoma is a serious eye disease that can lead to permanent vision loss if not detected and treated in time. Here are some key figures and facts about glaucoma:

Glaucoma affects about 80 million people globally (2020).
It is estimated that this number will rise to over 110 million by 2040 due to the aging population.
Glaucoma is the second leading cause of blindness worldwide, after cataracts.
About 10% of people with glaucoma become blind despite treatment.
Approximately 90,000 Danes have glaucoma, but many are unaware of it, as the disease often develops without symptoms in the beginning.
It is estimated that up to 50% of people with glaucoma do not know they have the disease.
Glaucoma is most common among people over 40, and its incidence increases with age.
People with a family history of glaucoma have up to 4-9 times higher risk of developing the disease.