What is glaucoma?

Glaucoma, often termed the “silent thief of sight”, is an eye disease that affects your eye’s optic nerve, usually caused by a pressure buildup in the eye due to poor drainage. Each eye has an optic nerve that relays information on things we see to our brain. Glaucoma is a serious eye disease that is often asymptomatic and should be treated as soon as possible to slow down or even halt its progression.

There are two types of glaucoma:

1. Open-angle glaucoma

This is the most common type of glaucoma that occurs when the eye is not draining as well as it should be. This type of glaucoma progresses gradually. It is painless and has no symptoms at first. However, this type of glaucoma can be detected early with regular eye exams.

2. Angle-closure glaucoma

This type of glaucoma occurs when the iris is too close to the drainage angle of the eye, so the iris ends up blocking the drainage angle. When the drainage angle is completely blocked, eye pressure rises rapidly, resulting in sudden and severe symptoms. Such cases are considered an emergency and an ophthalmologist should be consulted immediately.

Causes of glaucoma

Our eyes constantly produce fluid called aqueous humour. New aqueous should flow in while the same amount flows out to maintain normal eye pressure. However, if the drainage angle is not correct, the fluid cannot flow out and will build up in the eye. This results in eye pressure increasing, which may damage the optic nerve.

Some people are at higher risk of getting glaucoma than others. Such risk factors include:

  • Age (Risk of glaucoma increases from 50 years of age onwards)
  • Asian, Hispanic or African descent (due to genetic predisposition)
  • Existing medical conditions eg. diabetes, hypertension
  • Eye conditions eg. previous eye injury, high myopia (nearsightedness)
  • Long-term use of steroid medications

There are no specific lifestyle activities or diets that are linked to glaucoma, nor are there any definite ways to prevent glaucoma. The best thing that can be done in cases of glaucoma is early detection and treatment.

Signs and symptoms of glaucoma

The two types of glaucoma have differing signs and symptoms.

1. Open-angle glaucoma

One may not notice any vision loss until glaucoma is in its advanced stage. As the disease progresses, blind spots develop in one’s peripheral (side) vision. As this type of glaucoma tends to not show symptoms until damage is severe, it is important to go for regular eye exams, as eye exams are able to pick up on the abnormal eye pressure or any damaged optic nerve before you experience any symptoms.

2. Angle-closure glaucoma

One typically does not experience symptoms before an attack. Early symptoms of an oncoming attack include blurred vision, halos, mild headaches or eye pain.

During an attack, one may experience:

  • Severe eye pain, typically associated with headache 
  • Redness of eye
  • Blurry vision
  • Nausea and vomiting

People with such symptoms should see an ophthalmologist immediately.

How often does glaucoma lead to blindness?

Statistically, about 15% of glaucoma patients lose ability to read in one eye. However, glaucoma progresses at different rates for different individuals, the majority of glaucoma patients never reach blindness. If left untreated, glaucoma causes  one’s peripheral vision to start becoming blurry. Overtime, their central vision will be blurred as well, which leads to the person going blind.

Early detection of glaucoma is crucial in preventing any adverse consequences. With early detection, glaucoma is highly treatable. However, if glaucoma is left untreated until the optic nerve is damaged, the damage cannot be reversed, although further possible damage can still be prevented by visiting an ophthalmologist. Hence, it is important to go for regular eye exams to detect such eye diseases as early as possible, especially if you are at higher risk for them.

Treatment of glaucoma

Glaucoma is a progressive disease. While it cannot be completely cured, its progression can be slowed down or even halted through treatment.

1. Medication

Glaucoma is usually controlled with eyedrop medication. Some of these eyedrops help by reducing the amount of fluid (aqueous humour) your eye produces, while others may help fluid flow better through the drainage angle, thereby reducing your eye pressure.

As these eyedrop medicines are absorbed into the bloodstream , they may cause some side effects, such as stinging or itching sensations. Any side effects should be reported to your ophthalmologist.

2. Surgery

This option is usually undertaken if medical treatment with the eyedrops are not effective. The most common surgery is trabeculectomy, where an opening is created for the fluid in the eye to drain out. The fluid is absorbed by tissue around your eye and eye pressure is relieved.

There are other types of surgery used to treat more complicated cases of glaucoma.

3. Laser treatment

This is usually used for patients with angle-closure glaucoma. Iridotomies involve using a laser to create a tiny hole in the iris to help fluid flow to the drainage angle.

Book an eye exam to make sure your eyes are safe from the “silent thief of sight”.

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