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A Singapore Glaucoma Specialist’s Guide to Glaucoma (2022)

“I can't have glaucoma — I can still see clearly.” As an ophthalmologist with over 17 years of experience, I have encountered many glaucoma patients who do not have any symptoms, especially in the early stages of their condition.

More than 90%[1] of patients with glaucoma remain undiagnosed worldwide; detection is tremendously crucial, especially in the early stages – because once there is eye nerve damage, the loss in vision is irreversible.

Glaucoma is a leading cause of blindness globally, and is often poorly managed in developing nations: 

  • WHO estimates that approximately 4.5 million people worldwide[1] are blind due to glaucoma
  • Glaucoma accounts for moderate and severe visual impairment in 7.7 million people globally[2].

While this widespread disease cannot yet be cured, glaucoma treatment in Singapore is of paramount importance to prevent further irreversible visual loss.

If you’re living with glaucoma in Singapore, read on to find out more about this blinding condition and the available options for glaucoma treatment. 

What is glaucoma? 

Glaucoma is a disease that damages your eye nerve. The condition usually occurs when fluid (aqueous humour) builds up in your eye, therefore increasing the pressure in your eye, and eventually damaging the eye nerve.

Our eyes naturally create fluid that provides oxygen and nourishment to the rest of the eye. In a normal eye, as new fluid is produced within our eyes, the same amount of fluid drains out via our drainage angles. This process keeps the intraocular pressure (IOP) or eye pressure stable.

However, in eyes with glaucoma, the drainage angles do not drain fluid adequately, causing fluid to accumulate within the eye, increasing eye pressure and eventually damaging the eye nerve. 

If left untreated, glaucoma can eventually lead to permanent blindness. As early glaucoma does not have any symptoms, it is often not detected until it’s too late, when damage to the eye nerve is severe. Hence, glaucoma is often called “The Silent Thief of Sight”.

What are the types of glaucoma? 

Glaucoma can be a primary (not associated with other eye diseases) or secondary (associated with other eye diseases) condition.


It can be further categorised under open-angle (the drainage angles are open and fluid can easily enter the drainage pathway) and closed-angle glaucoma (the drainage angle is closed because the iris is contact with the cornea, hence preventing fluid from entering the drainage pathway).

Type of glaucomaWhat it is
Primary open-angle glaucomaThis is the most common form of glaucoma worldwide. The drainage angle is open and fluid can easily enter the drainage pathway. However, the drainage pathway itself is not functioning well, hence reducing drainage of fluid from the eye.
Primary angle-closure glaucoma, or narrow-angle glaucomaThis occurs when the drainage angle is closed because of contact between the iris and the cornea. Hence, fluid is unable to enter the drainage pathway, resulting in increased eye pressure. In eyes with acute angle-closure, the drainage angles are completely closed, resulting in markedly raised eye pressure. This is a medical emergency which can cause rapid blindness and requires immediate treatment.
Normal-tension glaucoma, or low-tension glaucomaThis occurs when the eye nerve becomes damaged at normal levels of eye pressure. Normal tension glaucoma is associated with diseases such as high blood pressure, diabetes and sleep apnoea.
Secondary glaucomaThis occurs because an associated condition has resulted in increased eye pressure and damage to the eye nerve. Eye trauma, inflammation, medication use, and poorly controlled diabetes can cause secondary glaucoma. Traumatic glaucoma can occur immediately, or even years after an injury.
Pigmentary glaucomaThis is a type of open-angle glaucoma that occurs when small pigment granules on the iris are chafed off and become trapped in the eye’s drainage pathway.
Exfoliative glaucomaThis occurs when a white, flaky, dandruff-like material occludes the drainage pathway of the eye, increasing eye pressure.
Neovascular glaucomaThis condition arises when abnormal new blood vessels develop on the iris and over the drainage angles. These vessels damage the drainage pathway, preventing fluid from flowing out of the eye. Poorly controlled diabetes can result in neovascular glaucoma .
Uveitic GlaucomaInflammation within the eye damages and obstructs the drainage pathway in the eye, hence resulting in raised eye pressure. Steroid used to treat the eye inflammation can also obstruct the drainage pathway, further elevating eye pressure.
Congenital GlaucomaThis is a rare and often hereditary condition caused by the abnormal development of the drainage pathway in a child.

What are the symptoms of glaucoma?

Early glaucoma (open-angle glaucoma and chronic angle-closure glaucoma) often has no symptoms. Visual impairment might not be noticeable until the glaucoma is advanced. 

As the increase in eye pressure and the visual loss is gradual in most patients, it typically and initially presents as loss of peripheral vision. As the glaucoma progresses, one’s vision becomes increasing constricted, until the patient is eventually left with only a tiny central island of vision.

At this stage, the patient will only be able to see what is directly ahead of him/her.

In a minority of patients, the eye pressure increases suddenly to very high levels, resulting in acute glaucoma. This is often associated with closed angle glaucoma.

Open-angle glaucoma cannot be prevented. Closed-angle glaucoma, on the other hand, is preventable. In the early stages of the disease, a laser procedure called an iridotomy can potentially help to widen the drainage angles and prevent an increase in eye pressure. 

Early cataract surgery can also widen the drainage angles and has been shown in a large study[3] to be more effective in lowering the eye pressure and improving the vision compared with iridotomy. 

Is glaucoma common in Singapore?

In Singapore, glaucoma affects about 3% of those 40 and older, and nearly 10% of those aged 70 and above[4]. It is reported that while everyone has a 2.3% lifetime risk of glaucoma, first-degree relatives of glaucoma patients have a ten-fold increase in risk.

Here are the other risk factors for glaucoma:

  • Older age
  • Gender (Closed-angle glaucoma is more common in females)
  • Race (Closed-angle glaucoma is more common in Chinese individuals)
  • Short-sightedness / high myopia (Increases the risk of developing open-angle glaucoma)
  • Long-sightedness (Increases the risk of developing closed-angle glaucoma)
  • Prior eye injuries
  • Medical conditions (eg. diabetes, hypertension)
  • Co-existing eye diseases, such as inflammation and pigment dispersion
  • Steroid use

Should I be worried if I have glaucoma?

Damage to the eye nerve in eyes with glaucoma cannot be reversed, so if you have risk factors for glaucoma, it is important to have annual eye examinations. Even if you do not have any of the above risk factors, it is recommended to have regular eye examinations after the age of 40. 

In addition, to keep your eyes healthy, I encourage the following: 

  • Wear appropriately powered spectacles
  • Wear sunglasses with UV protection
  • Brighten your lighting at home and at work
  • Exercise moderately 
  • Eat a healthy, well-balanced diet with leafy green vegetables and rich in anti-oxidants

If you have both cataracts and glaucoma, you can opt for combined cataract and glaucoma surgery which will not only improve your quality of life but will also reduce or eliminate your need for glaucoma medications.

Some ophthalmologists undergo further subspecialty training (fellowships) to become glaucoma specialists. Early glaucoma may be difficult to diagnose, and a review by a Singaporean glaucoma specialist may be necessary for a definitive diagnosis of glaucoma to be made, and for the type of glaucoma to be identified. 

If you have risk factors for glaucoma or if you experience symptoms of acute glaucoma listed above, please visit your ophthalmologist immediately, as early glaucoma treatment is crucial in Singapore.

How is glaucoma tested in Singapore? 

When it comes to glaucoma screenings in Singapore, you can expect to undergo the following:

  • Tonometry. This measures your eye pressure.
  • Gonioscopy​. Your eye doctor places a special lens on your eye to determine whether you have open or closed angles. Anaesthetic eye drops will be given prior to the placement of the lens on your eye, making this examination quick and painless.
  • Visual Fields Assessment. This test is carried out in a dark room with a white screen. Patients will be tasked to press a button when they see flashes of light, of varying intensities and sizes on this screen. This test assesses your peripheral vision, hence identifying any damage to the eye nerve.
  • Eye nerve assessment. Your specialist will look at the back of your eye through a special lens to assess the health of your eye nerve. Photographs and specialised scans of the eye nerve may also be taken.

Glaucoma surgeons in Singapore are likely to employ various methods to diagnose glaucoma. 

How is glaucoma treated in Singapore?

Glaucoma treatment in Singapore often starts with prescription eye drops. 

Eye drops work by reducing the production of aqueous fluid, or by increasing fluid drainage. The use of daily eye drops is usually life-long, and compliance is crucial. Some patients may require several types of glaucoma eye drops in order to lower their eye pressure to an acceptable level. 

If glaucoma eye drops are not able to reduce the eye pressure sufficiently, if the patient is not compliant with the eye drop regime or if there are significant side effects from the eye drops, other treatment options for glaucoma in Singapore are: 

  • Intravenous or oral anti-glaucoma medications might be prescribed to reduce the high eye pressure, but these should not be used long-term in view of the potential side effects on the body. 
  • Glaucoma surgery
    • Tube implant surgery, where a device is inserted into your eye to allow excess fluid to drain out.
    • Trabeculectomy, where an opening is created for the fluid in the eye flow out onto the surface of the eye.
    • Minimally Invasive Glaucoma Surgery (MIGS), which involves using tiny incisions and/or microscopic devices to drain fluid out of the eye internally or externally.

Read: Is surgery always necessary to treat glaucoma? 

  • Glaucoma laser treatment 
    • Selective Laser Trabeculoplasty (SLT), where a laser is used to increase the outflow of fluid from your eye.
    • Laser Iridotomy, where laser is used to create a microscopic hole in the iris to widen the angles in the eye, allowing more fluid to enter the drainage pathway. Laser iridotomy is usually performed in patients with angle-closure glaucoma.
    • Laser Iridoplasty, where laser burns on the peripheral iris widens the angles in the eye, allowing more fluid to enter the drainage pathway. Laser iridoplasty is used to treat eyes with plateau iris syndrome, a type of angle closure glaucoma.

It is important to tell your eye doctor if you have the following conditions or drug allergies, as it will affect the type of treatment you are suitable for:

  • Any form of drug allergies (especially sulphur allergies)
  • Heart disease (especially heart block, or heart failure)
  • Kidney disease
  • Asthma

Do note that glaucoma eye drops might have side effects, which may affect some patients more than others. It is important to inform your eye doctor if you are experiencing any side effects from glaucoma eyedrops and please follow your eye doctor’s instructions when administering these eye drops.

Can I use MediSave for Glaucoma treatment in Singapore?

Yes, part of the costs for surgery and laser procedures are Medisave-claimable depending on your condition. Please speak to our friendly staff for more information.

If you suspect that you might have glaucoma, there is no time to waste – see a glaucoma specialist as soon as possible. Early treatment of glaucoma can preserve vision. 

Do you have any questions for me? Feel free to drop me a message

References:

  1. World Glaucoma Week 2021 | National Health Portal Of India. (n.d.). Www.nhp.gov.in. Retrieved October 11, 2022, from https://www.nhp.gov.in/world-glaucoma-week-2021_pg
  1. Glaucoma in Singapore: Stats, Risk Factors and Prevention - HealthXchange. (n.d.). Www.healthxchange.sg. Retrieved October 11, 2022, from https://www.healthxchange.sg/seniors/ageing-concerns/glaucoma-singapore-stats-risk-factors-prevention
  2. Azuara-Blanco, A., Burr, J., Ramsay, C., Cooper, D., Foster, P. J., Friedman, D. S., Scotland, G., Javanbakht, M., Cochrane, C., Norrie, J., & EAGLE study group (2016). Effectiveness of early lens extraction for the treatment of primary angle-closure glaucoma (EAGLE): a randomised controlled trial. Lancet (London, England)388(10052), 1389–1397. https://doi.org/10.1016/S0140-6736(16)30956-4
  3. https://www.healthhub.sg/a-z/diseases-and-conditions/380/glaucoma 

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    Dr Chelvin Sng of Chelvin Sng eye center

    Dr Chelvin Sng

    Adjunct Associate Professor
    Senior Consultant Ophthalmologist
    ✓ 4 Gold Medals (Specialist Accreditation Examination)
    ✓ "Top 50 Rising Stars” (2017), “Top 100 Female Ophthalmologists” (2021)
    and "Top 100 Ophthalmologists" (2022)
    ⋆ Global Ophthalmologist Power List (voted by peers worldwide)
    ✓ Cambridge University Graduate with Triple First Class Honours and Distinctions

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