10th-16th March is World Glaucoma Week. The aim of the week is to raise awareness about glaucoma and motivate people to have regular eye checkups to eliminate blindness caused due to glaucoma.
Glaucoma is one of the leading cause of blindness in the world. According to a 2014 study, glaucoma affects more than 70 million people worldwide. In 2015, there were 57.5 million people worldwide with primary open-angle glaucoma, a type of glaucoma, and it was expected to increase to 65.5 million people by 2020. In India, glaucoma is the leading cause of irreversible blindness with at least 12 million people affected and nearly 1.2 million people blind from the disease. Hence, this world glaucoma week, let’s learn a bit about what is glaucoma, the risk factors and symptoms of glaucoma and when to go to an ophthalmologist.
What Is Glaucoma?
Glaucoma is a set of progressive optic nerve condition that can lead to severe vision problems and blindness. It can damage the optic nerve, which is known to mediate visual information to the brain from the eyes. It is mostly caused due to an increase in the eye pressure which over time can severely damage the optic nerve and may lead to permanent blindness. If detected early, you can prevent the loss of vision and delay the damage caused to the nerve.
Some of the common types of glaucoma are
Open-angle glaucoma: It is the most common type of glaucoma. Also known as chronic glaucoma, it usually shows no signs or symptoms but causes a slow loss of vision. In this, there is no physical abnormality in the drainage structure but the fluid fails to flow properly into the cornea which impacts the optic nerve.
Angle-closure glaucoma: In this condition, the space between the cornea and iris that causes the fluid to drain becomes narrow. This causes a sudden buildup in the eye pressure, affecting the nerve. It is mostly seen in people with cataracts and farsightedness.
Congenital glaucoma: As the name suggests, this is a type of glaucoma that is present since birth. Children born with this condition have a defect in the eye which affects the normal fluid drainage thereby building pressure in the eye. This condition usually runs in families.
Secondary glaucoma: It is often a side-effect of an injury or trauma caused to the eye. This could also be due to cataracts, certain medications such as corticosteroids, inflammation in and around the eyes, a tumour of the eyes, or conditions such as pigment dispersion.
What Causes Glaucoma?
The eye produces a fluid known as aqueous humour which keeps the eye moist. This fluid leaves the eye through openings in the cornea and iris. However, any damage or blockage of these openings can increase the pressure in the eye, which is known as intraocular pressure. This increase in the eye pressure can damage the optic nerve, which in turn can affect the vision, even leading to blindness.
The exact cause of an increase in eye pressure is not known. But it is believed that several factors can increase the pressure in the eyes which include high blood pressure, diabetes, poor blood flow to the optic nerve, medications such as corticosteroids, blocked drainage in the eyes and use of dilating eye drops.
Are You At Risk Of Glaucoma?
There are several factors that can increase your risk of glaucoma. The risk factors for glaucoma include:
Age: The risk of glaucoma increases with age. People over 60 years are known to be at high risk of the condition.
Race & Ethnicity: For people with African-American origin the risk begins at the age of 40. People of Asian descent are at a higher risk of suffering from angle-closure glaucoma.
Family history: If you have a family history of glaucoma, then you are at high risk of suffering from the condition as certain types of glaucoma run in families.
Diabetes mellitus: People suffering from diabetes or those with a family history of diabetes are at high risk as uncontrolled blood glucose level can cause nerve damage.
What Are The Signs And Symptoms Of Glaucoma?
Many patients with glaucoma are asymptomatic and do not know they have the disease. More than 90 per cent of these cases remain undiagnosed due to the lack of symptoms of glaucoma. However, there are certain signs and symptoms of glaucoma that should not be ignored. These include:
Halos around light: When the pressure in the rises quickly due to closed angle glaucoma, the cornea becomes waterlogged which can affect the vision leading to halos around lights.
Pain in the eyes: It is mostly seen when there is a sudden buildup of pressure. It does not act as one of the characteristic features/symptoms of glaucoma when the rise in pressure is gradual and not sudden.
Tunnel vision: It is one of the common symptoms of glaucoma. In this, the pressure on the nerves can damage the retinal nerve fibres which can lead to a characteristic pattern of vision loss. This leads to tunnel vision in which the peripheral vision is blocked. For example, when seeing a photo, you may not be able to see the peripheral picture but can see the centre portion of the picture with clarity. This can be seen when undergoing testing of the eyes.
Changes in the optic disc: The rise in intraocular pressure can lead to cupped, pale optic disc which acts as the key symptoms of glaucoma.
Enlargement of the eye: In kids below three years of age, enlargement of the eye due to raised intraocular pressure can occur. It is one of the characteristic symptoms of glaucoma. In adults, the eye cannot enlarge greatly because growth has ceased.
When To Consult an Ophthalmologist?
Most people with the condition do not show any symptoms early in the course of the disease. Moreover, it can lead to slow and progressive damage of the optic nerve which makes it difficult to detect the condition. Hence, it is advised to see an ophthalmologist if you are above 40 years of age, have a family history of glaucoma or other eye disorders, suffer from diabetes or have any smyptoms of glaucoma. It is wise to get a complete eye exam done once every two years to detect any changes in the vision.
The diagnostic tests for the condition include ophthalmoscopy, tonometry and perimetry along with a physical examination of the eyes and checking eye pressure. Based on your condition and diagnosis, the treatment options include the use of eye drops, laser therapy, or surgery to slow down the loss of vision by lowering intraocular pressure.
(The article is reviewed by Dr. Lalit Kanodia, General Physician)
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