Glaucoma

Glaucoma is an eye disease known to be associated with an increase in intraocular pressure. As the disease progresses, the eye’s optic nerve which sends images to the brain becomes damaged and can result in loss of field of vision leading up to blindness within a few years. Glaucoma is the 2nd most common cause of vision loss, accounting for 40% of blindness in Singapore.

How does Glaucoma develop?

The front part of the eye is filled with a clear fluid known as aqueous humor. This fluid maintains the structures within the front of the eye and is usually circulated through the pupil and out through the trabecular meshwork, which are the drainage channels of the eye. When the channels are blocked, there is an imbalance between the production and drainage of the fluid, leading to a build-up of fluid in the eye. This results in an increased eye pressure.

However, not everyone with increased eye pressure will develop glaucoma. The onset of the disease will depend on the level of pressure the optic nerve can tolerate without getting damaged and this level will vary from person to person. Some people are able to withstand higher levels of eye pressure as compared to others. When the pressure goes beyond what the eye can tolerate, there will be damage to the optic nerve and vision loss can occur.

There is no exact cause to why the drainage channels get blocked, but there are a few possible risk factors. To make matters worse, there are usually no symptoms presented especially in the early and moderate stages. When symptoms start to appear, for example loss of vision, the condition has generally progressed to become more severe. Regular screening and early detection are key to manage the disease as soon as possible to prevent visual loss.

Types of Glaucoma

There are two types of glaucoma, namely Open-Angle and Closed-Angle.

Open-angle glaucoma is the most common type of its disease. It is largely related to age and therefore results in a chronic condition. Due to the natural aging process, the drainage process gradually becomes more clogged over time, even when the channels are opened. This causes the fluid to be retained in the eye and with time, the build-up increased the pressure within the eye ball. There no usually no symptoms presented in such cases.

Closed-angle glaucoma is less common and may be acute or chronic. As its name suggests, closed-angle glaucoma happens when the entire drainage angle is completely closed and blocks off the drainage channels. This can cause a sudden build-up of pressure in the eye, resulting in an acute onset.

Symptoms experienced could include:

  • Pain in the eye
  • Redness of the eye
  • Headache or nausea
  • Blurred vision
  • Presence of “haloes”

When this happens, seek medical attention immediately. Surgery might be needed to allow the fluid to be drained out.

Am I at risk of developing Glaucoma?

If you are above 40 years old and have a family history of glaucoma, it is highly advisable to go for a complete eye assessment every 1 to 2 years.
There are other possible risk factors that could contribute to developing glaucoma:

  • Chronic diseases like diabetes and high blood pressure
  • Ethnicity
  • Eye injuries
  • Severe myopia
  • Use of steroids

Unfortunately, glaucoma cannot be cured but the progression of the disease can be controlled. Treatment is dependent on the type of glaucoma and the stage of the condition. Generally, glaucoma can be successfully managed with:

  • Medicated eyedrops
  • Oral medication
  • Laser treatment
  • Surgery
  • A combination of the above

For patients with glaucoma, it is important to take your medication religiously as prescribed by your eye doctor. It is essential to visit your doctor regularly to monitor your eye pressure, visual field and state of the optic nerve.