Glaucoma: Types, Symptoms, Causes, Risks, Diagnosis, Treatment, Prevention and Prognosis

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Illustration of normal vision and of glaucoma

1Overview

A glaucoma is an eye condition that causes damage to the optic nerve, the one responsible for transmitting information and images to the brain. It is crucial to have good vision, and when it’s damaged, it may lead to an abnormally high pressure inside the eyes, called intraocular pressure.

If the damage to the optic nerve continues, it may lead to permanent blindness. In fact, glaucoma is the leading cause of vision loss among people who are over 60 years old. However, glaucoma-induced blindness is preventable if it’s treated early and accordingly.

If you are over 40 years old and has a family history of glaucoma, a complete eye exam every one to two years is important. Moreover, people suffering from medical conditions like diabetes are at a higher risk of glaucoma.

Across the globe, an estimated 60 million people have glaucoma. The number may increase to about 80 million by 2020.

In the United States alone, there are over three million people who live with glaucoma. Unfortunately, only half of these people are aware of their condition.

Consequently, over 120,000 people are blind because of glaucoma, accounting for about 9 percent to 12 percent of all vision loss cases in the country. The eye disease costs the economy of the United States about $2.86 billion each year regarding productivity losses and direct costs.

Glaucoma, however, affects African Americans and Hispanics more in the country.
In fact, it has become the leading cause of vision loss among these ethnicities.

2Types of Glaucoma

Closed-angle glaucoma (acute angle-closure glaucoma)

Closed-angle glaucoma is a type of eye condition that acts like a thief in the night. It comes suddenly, and the patient would experience pain and abrupt vision loss. Because of the rapid progression of the symptoms, the patient will most likely seek medical help, resulting in early detection and treatment.

Low-tension glaucoma

This is a rare form of glaucoma characterized by a normal eye pressure but with a damaged optic nerve. The cause has been linked to the lack of blood supply to the optic nerve.

Primary open-angle glaucoma (chronic glaucoma)

Unlike closed-angle glaucoma, primary open-angle glaucoma involves a chronic progression of optic nerve damage. As a result, the patient may not feel any symptoms.
However, because the patients do not experience the symptoms, they may go unnoticed. Hence, they do not seek medical help until permanent damage already occurred.

Pigmentary Glaucoma

Pigmentary glaucoma is a type of open angle glaucoma which develops during early or middle adulthood. In this type of glaucoma, pigment cells come from the iris and become distributed within the eye. When there is a buildup of the cells, it may increase intraocular pressure.

3Symptoms

The signs and symptoms of glaucoma are different depending on the stage of the disease and the type of the condition.

Open-angle glaucoma

  • Tunnel vision in severe cases
  • Patchy blind spots, often in both eyes

Acute-angle glaucoma

  • Eye pain
  • Nausea and vomiting
  • Blurred vision
  • Halo surrounding lights
  • Redness in the eyes
  • Severe headache
  • Permanent blindness (if the condition is not properly and immediately treated)

4Causes

Glaucoma is caused by a blockage in the area of the eye that allows fluid to drain from it. As a result, this would lead to damage to the optic nerve. When the nerve slowly deteriorates, the patient may have blind spots and eventually, lead to permanent vision loss.

Normally, the eye constantly creates aqueous humor, the fluid inside the eye. When this fluid flows into the eyes, the same amount should be drained out. This is to maintain the normal pressure inside the eye. But if the drainage angle, the area where the fluid drains out, is not working properly, fluid would build up.

When the pressure inside the eye increases, it would damage the optic nerve, which is made of a million tiny nerve fibers. It’s responsible for transmitting images to the brain.

Usually, glaucoma runs in families and some people, there is a gene passed in families related to high eye pressure and damage to the optic nerve.

5Risk Factors

Some factors that may increase your risk of developing glaucoma. These include:

Age

Older adults have a higher risk of developing glaucoma. The most common type of this eye problem affects around one in ten people who are over 75 years old.

Family History

Glaucoma runs in families. If you have a relative or immediate family who had glaucoma, you are at a heightened risk of developing it as well.

Ethnicity

Individuals who are of Caribbean, Asian or African descent are at a higher risk of developing glaucoma.

Other factors:

  • Having intraocular pressure
  • People who are 60 years old and above
  • People with underlying health problems like diabetes, high blood pressure, sickle cell anemia and heart disease
  • Other eye conditions and eye surgery
  • Consuming corticosteroids in the eyes for a prolonged period
  • Early estrogen deficiency

6Diagnosis

Glaucoma can be detected during a routine eye test even before noticeable symptoms appear. Hence, it is important for people to have routine eye checkups, especially those who have a family history of the condition.

Many painless and easy tests are done to help diagnose glaucoma. These include:

Dilated eye exam

This exam is done to observe the optic nerve for signs of damage. The doctor will put eye drops to help dilate the pupils. With a special magnifying lens, the doctor will assess the inside of the eye.

Visual acuity test

This is a simple exam to measure how well the patient can see at different distances.

Tonometry

This test measures the pressure inside the eye. A special instrument dubbed as tonometer is used.

Visual field test

This test gauges the person’s peripheral vision. The loss of peripheral vision is a sign of glaucoma.

Pachymetry

This is a test to measure corneal thickness.

7Treatment

There are various ways to treat glaucoma. Most doctors use medicines, surgery, and eye drops.

Eye drops

Eye drops are used to reduce the formation of fluid in the eye or increase outflow.

Prostaglandins

These eye drops help reduce the pressure inside the eye and boost outflow of the liquid.

Beta-blockers

These eye drops help reduce the production of aqueous humor. As a result, the intraocular pressure is maintained in a stable status.

Carbonic anhydrase inhibitors

These eye drops are not usually used in glaucoma. However, these can help lower the production of fluid inside the eye.

Alpha-adrenergic agonists

This is an eye drop that increases the outflow of fluid from the eye.

Miotic or cholinergic drugs

These medicines are also used to increase the outflow of fluid from the eyes.

Oral Medicines

The doctor may prescribe oral medicines if the eye drops do not work. However, only a licensed doctor will decide on which medicine to take. Never self-medicate.

Surgery

Conventional surgery involves the creation of a new opening for the fluid to flow. This is usually done after taking medicines and laser surgery but have not been able to control pressure. This surgery is usually done on one eye at a time, and the surgeries are four to six weeks apart.

Laser Surgery

Laser surgery is used to help increase the flow of the fluid from the eye. This is done to patients with open-angle glaucoma. The most common procedures include trabeculoplasty, iridotomy,

Other surgical procedures:

  • Filtering surgery
  • Draining tubes
  • Electrocautery
  • Laser trabeculoplasty.

8Prevention

Glaucoma can’t be prevented, but early detection and treatment may help reduce the chances of blindness and other complications.

Regular eye check-ups are the best way to prevent against glaucoma damage and effects on the eyes. A consultation for glaucoma is done:

  • Before turning 40 years old, every two to four years
  • For people between 40 and 54, the test should be done one to three years
  • For people between the ages of 55 and 64, the test is done every one to two years
  • For people over 65 years old, yearly or every two years consultations are important.

However, here are self-care steps to help detect the condition early and reduce vision loss or slow its progress.

  • Be aware if you have a family history of glaucoma. You should get regular eye care.
  • Engage in safe exercise. There are appropriate exercises for you and make sure you have regular and moderate exercise each day. Regular exercise will benefit not only the overall health individual but it also helps lower intraocular pressure.
  • Talk with your doctor if you have specific questions or concerns about starting an exercise program.
  • Protect your eyes. Serious eye injuries may lead to glaucoma. Always wear eye protection when working in dangerous places, using power tools and high-intensity sports activities.

9Prognosis

Glaucoma can cause blindness if it’s not treated appropriately. About 10 percent of people with glaucoma who were treated may still experience vision loss.

Most people with glaucoma may not develop optic nerve damage or permanent blindness. However, it is important to detect the disease early on to prevent serious complications and the progressive loss of peripheral vision, and eventually irreversible blindness.