Every year, thousands of people are losing their vision. The culprit is an eye disease called glaucoma.

So, what is glaucoma? Glaucoma is the leading cause for irreversible blindness worldwide. Often dubbed as a “silent killer of vision”, it develops without any obvious symptoms in its early stages. By the time the patient has noticed the impairment in their vision, more often than not, it would already have been too late. In fact, as much as 40% of the vision can be lost without the patient noticing it! This condition has been projected to increase 101% by 2040 in a Singapore consensus study.

Read also: Common Ocular Conditions

What is glaucoma?

Glaucoma is a condition where the nerve of the eye, called the optic nerve, is damaged. The damage progresses with time and is irreversible. There are many causes that damage the optic nerve. The most common being a build-up of pressure in the eyeball because the fluid is unable to drain efficiently.

A good analogy will be to compare the eye to the air pressure of a car tyre. Just as a tyre needs a specific amount of air pressure to retain its shape and stay firm, the eyeball requires the correct amount of Intra-Ocular Pressure (IOP) to be able to function properly. When there is an increase in eye pressure which cannot be relieved, the prolonged elevated pressure continues to push against the optic nerve causing damage. This process is irreversible, and so is the vision loss.

Photo showing optic nerve damage in glaucoma eye

If left untreated, this eye condition will lead to diminished visual field (particularly in the peripheral line of sight) and eventually, blindness will creep in.

What are the different types of glaucoma?

In general, there are 5 different types of glaucoma, which is caused by a number of different factors:

1. Primary Open-Angle Glaucoma

The most common form of glaucoma, open-angle glaucoma, usually has no symptoms prior to advanced peripheral vision loss. When significant visual field loss occurs, one may experience patchy vision or blind spot. However, the irreparable damage and vision loss may be so slow that it goes unrecognised before any symptoms become apparent.

2. Chronic Angle-Closure Glaucoma & Acute Angle-Closure Glaucoma

Another common form of glaucoma in Asians is angle-closure Glaucoma. In acute angle-closure glaucoma, the flow of the fluid in the eye, called aqueous humor, is suddenly blocked. This causes a rapid build-up of fluid in the eye and thus, causing very high Intra-Ocular Pressure. If you experience sudden symptoms such as severe eye pain, one-sided headache, nausea, together with eye redness and blurred vision, you should see your eye specialist immediately. The chronic angle-closure glaucoma, like open-angle glaucoma, has no symptoms prior to advanced peripheral vision loss. 

3. Normal Tension Glaucoma

It may come as a surprise to you, but patients without increased Intra-Ocular Pressure may also sustain damage to their optic nerves. The mechanism is not well understood. Recent scientific studies suggest that it might be associated with increased risk of neurodegenerative conditions such as Alzheimer’s Disease or Dementia.

4. Secondary Glaucoma

Secondary glaucoma is caused by other existing medical conditions, leading to an elevated level of eye pressure. For instance, serious eye trauma and inflammation, poorly controlled diabetes, tumour, cataract or retinal blood vessel blockage can lead to this condition, resulting in optic nerve damage and vision loss. For patients with secondary glaucoma, treatment must address both the elevated IOP and the underlying medical cause. 

5. Congenital and Juvenile Glaucoma

Though it is uncommon, but it is possible for infants and children to develop glaucoma. In this case, the damage of optic nerves can result from the slow or blockage in the eye aqueous drainage or an underlying medical condition. Congenital glaucoma are hereditary and can be passed down through the abnormal recessive genes.

How do I recognise the symptoms of glaucoma?

Recognising glaucoma in the early stages can be tricky but vital. Since it often has no apparent symptoms prior to significant peripheral vision loss, many glaucoma patients are unaware that they are suffering from this disease. The vision loss is so gradual that you may not even notice it until the condition is at an advanced stage.

If you experience any of the following symptoms, you should seek immediate help:

As you may have noticed, these are symptoms common to many other eye diseases. They can easily be missed out or brushed off as other “not-as-serious” eye problems. Given the silent nature of glaucoma, we would urge our patients/ readers to undergo regular eye checks which allows early detection and intervention of the disease.

Am I at risk for glaucoma?

Generally, the risk of glaucoma increases with age. Although the most common form of glaucoma affects mostly people above 60 years old, you should not let your guard down as it can affect people of all ages. Other risk factors of this eye disease include:

What can I do to prevent or lower my risk of glaucoma?

While there are no known ways to prevent glaucoma entirely, blindness or significant vision loss could be avoided if the disease is recognised in the early stages. This is why if you belong to either of the above higher risk groups, we will strongly recommend you to see an eye doctor for a regular comprehensive eye exam. Your eye doctor will tell you how often to have follow-up exams based on the results of this eye health screening.

Nonetheless, medical experts recommend a healthy lifestyle for those who are at risk of developing glaucoma, such as to:

There is a silver lining in all of this. Other than being able to slow down the progression of glaucoma, you will be able to enjoy a vibrant, active life with a healthy body and a healthy mind. Remember, making gradual small changes to your daily lifestyle can go a long way.

I have been diagnosed with glaucoma – now what?

While there is no cure for glaucoma at this point of writing, there are several ways to slow down glaucoma progression. 

The goal of glaucoma treatment is to lower the Intra-Ocular Pressure (IOP) to an acceptable range, thus reducing damage to the optic nerves. What one has got to bear in mind is that glaucoma treatment is a lifelong process and must be continued throughout life, and that any vision loss is permanent and irreversible.

Depending on the type of glaucoma, there are three types of management options, which can be classified into:

1. Medical Treatment 2. Surgical (Incisional) Treatment 3. Laser Treatment
What is it? This is the most common form of glaucoma treatment. It comes in the form of eye drops regime but can also come in the form of intravenous or oral anti-glaucoma medications, especially for the acute glaucoma attack. This is usually administered if medical therapy fails. The most common form is trabeculectomy, where the surgeon will make a cut in the eye, creating an outflow channel for the eye aqueous fluid into the surrounding eye tissue, thus significantly reducing Intra-Ocular Pressure.
A newer type of surgery termed Minimally-invasive Glaucoma Surgery (MIGS) involves using micro-implants in the form of stents or shunts to achieve significant reduction of Intra-Ocular Pressure with lower surgery risks and downtime.
Laser treatment can be carried out in patients with angle-closure glaucoma (laser iridotomy, laser iridoplasty) or in patients with open-angle glaucoma (Selective laser trabeculoplasty (SLT)). SLT has become an evidence-based first-line treatment for open-angle glaucoma, especially for patients who cannot tolerate or are not compliant to medical treatment.
Pros Requires high level of patients’ compliance. Effective even for patients with severe glaucoma. Minimally-invasive procedures with a good safety profile, especially in the short-to-medium term Lasers are non-invasive procedures with good safety profile.
Cons Some side-effects may be experienced. Carry surgical risks, particularly for the larger incisional procedures Less IOP reduction as compared to conventional glaucoma surgeries, more suitable only for patients with mild to moderate glaucoma.

Can I use my Medisave to pay for my glaucoma treatments?

Unfortunately, glaucoma medications are not Medisave-claimable.

What is the key takeaway from this article?

Love your eyes? One of that you can protect your vision is by undergoing your regular comprehensive eye checks. Glaucoma cannot be self-detected. This is the only way you can make sure that this silent disease can be diagnosed early and nipped in the bud as early as possible.

According to the American Academy of Ophthalmology, these are the recommended intervals for eye exams:

If you would like to schedule an appointment for comprehensive eye exam or doctor’s consultation with Dr Philemon Huang, feel free to call us at 6733 5188 or email us at doctor@eyecare.com.sg!

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