Quick Facts: Glaucoma

Early symptoms: None in the early stages

Later symptoms: Progressive loss of side vision, eventual blindness

Risk factors: Family history of glaucoma, older age >40 years, short-sightedness or long-sightedness

Normal Optic Nerve

Optic Nerve with Glaucoma

Did you know?

  1. Quite a lot of us may have glaucoma: In Singapore, about 3 percent of us who are over 50 have glaucoma. This number increases as we get older so that by the time we are 70 almost 10 percent of us will have glaucoma.
  2. Some of us may have glaucoma and not know: glaucoma does not cause eye pain or change in our vision until it is advanced. That is why glaucoma is often called the “silent thief of sight”.
  3. Normal eye pressure for you may not be normal eye pressure for someone else: some of us with relatively low eye pressure can still have glaucoma called normal tension glaucoma.
  4. Treatment for glaucoma can prevent blindness: many of us think that there is no treatment for glaucoma. Actually there is treatment. Also, treatment can prevent blindness from glaucoma if it is started early.

What is glaucoma?

Glaucoma is an eye condition affecting the nerve at the back of the eyeball called the optic nerve. The optic nerve is progressively damaged due to eyeball pressure being too high for the nerve. The level of eyeball pressure at which damage occurs varies from person to person.

It is important to know that glaucoma causes nerve damage and nerve that is damaged cannot be repaired. So any damage caused by glaucoma is irreversible. Blindness from glaucoma is also irreversible.


So it is very important to identify and treat glaucoma as early as possible to preserve vision and prevent blindness. The only way to detect glaucoma is to get checked by an eye care professional because glaucoma has no symptoms until very late.

What are the types of glaucoma?

There are many different kinds of glaucoma, but the two commonest types in Singapore are open-angle glaucoma and closed-angle glaucoma. In Singapore about half of our patients will have closed-angle glaucoma.

Closed angle glaucoma is potentially preventable. In the early stages, your eye doctor can identify features that put you at risk for closed angle glaucoma before glaucoma develops. Treatments such as a laser procedure called an iridotomy or cataract surgery can help prevent progression.

Are you at risk for glaucoma?


Risk factors for glaucoma include

  1. Older age, especially if you are over 60 years of age
  2. Female: higher risk for closed-angle glaucoma
  3. Race: Chinese have higher risk for closed-angle glaucoma
  4. Family history of glaucoma
  5. Refractive error (spectacle power): being short-sighted increases the risk of open angle glaucoma and being long-sighted increases the risk of closed-angle glaucoma

How do we diagnose glaucoma?


Remember, glaucoma has no symptoms until very late. So the only way to diagnose glaucoma is by getting your eyes checked by an eye specialist to:

    1. measure your eyeball pressure or intraocular pressure
    2. check the drainage system of your eye called the drainage angle
    3. check your optic nerve for damage
    4. test how wide your vision through a test called the Humphrey Visual Field Analyser (HVF)
    5. obtain a computer analysis of your optic nerve called the Optical Coherence Tomography (OCT)
    6. measure the central thickness of your cornea (CCT)

Treatment for glaucoma

It is widely believed that there is no treatment for glaucoma, but that is not true. There is treatment which is aimed at reducing the eyeball pressure to stop any further damage from occurring. But it does not repair the damage that has already occurred. So treatment for glaucoma is best started as soon as possible to prevent any further damage to your vision.

Medicated eye drops. Most patients will be started on eye drops that need to be used on a daily basis. Some will require only one type of eye drop while others may require several different types of eye drops. The important thing to remember is that these eye drops need to be used every day so that the eyeball pressure is kept low every day.

Laser treatment. There are different types of laser treatment for glaucoma depending on the type of glaucoma you have. In some patients, laser treatment can be very effective, reducing or even eliminating the need for eye drops. Most lasers for glaucoma are clinic-based procedures and you will not need to stay in hospital. Usually most patients will also be able to return to work the next day if they wish. The types of laser treatments for glaucoma include:

  1. Laser iridotomy: this is a laser for patients with angle-closure glaucoma. This creates an alternative pathway for fluid in the eye to flow to the drainage system within the eye by applying laser to the iris and creating a channel through the iris called an iridotomy.
  2. Trabeculoplasty: this is a laser for patients with open-angle glaucoma. Laser is applied directly to the drainage system of the eye called the angle to improve flow through this drainage system. This improved flow through the drainage angle reduces the eye pressure.
  3. Cyclophotocoagulation: this is laser that is applied to the fluid producing part of the eye called the ciliary body. This laser aims to reduce fluid production within the eye which then reduces the eye pressure.

Surgery. Surgery for glaucoma involves creating a new drainage channel for fluid to leave the eye. There are 3 situations where surgery may be offered to you:

  1. Non surgical treatment of your glaucoma with eye drops or lasers are not working well enough in lowering your eye pressure.
  2. You are unable to apply eye drops, the most common reason being sensitivity and allergies to the eye drops,
  3. You have developed cataracts and are planning to have cataract surgery. Glaucoma surgery may then be performed as an “add-on” procedure together with your cataract surgery.

The types of glaucoma surgeries include:

    1. Trabeculectomy. This involves creating a channel for eye fluid (called aqueous humor) to leave the eye. The surgeon creates a pocket under the outer coat of the eye called the conjunctiva. This pocket is hidden under the upper eyelid and cannot be seen without lifting the upper eyelid. Aqueous humor will be able to drain out of the eye into this pocket and absorbed by tissue around the eye; resulting in a lower eye pressure. 
    2. Glaucoma drainage devices. This involves implanting a drainage device to help drain fluid from the eye. The fluid is directed to a collection area called a reservoir under the conjunctiva. 
    3. Minimally Invasive Glaucoma Surgery (MIGS). This group of surgeries are more recent advances in glaucoma surgery. They are called minimally invasive because they either involve implanting really small drainage implants or applying lasers through the same cataract surgery wound.  
    4. Cataract Surgery. Sometimes the removal of cataract alone can help with glaucoma by opening the drainage angle of the eye and thereby allowing between drainage of the fluid called aqueous from the eye. This then helps to reduce the pressure of the eye and improve the glaucoma.
    5. Combined Cataract and Glaucoma Surgery




The symptoms and possible related eye conditions/diseases in this section are for general reference only, and do not contain all visual symptoms or all possible related conditions or diseases. If you have any unusual vision symptoms, speak with your ophthalmologist.