Glaucoma, a leading cause of irreversible blindness, particularly affects women. Learn about its risks, symptoms, and the importance of early diagnosis.
Singapore, Singapore Sep 5, 2022 ALN: Did you know that glaucoma, an eye condition affecting the optic nerve, is the leading cause of irreversible blindness worldwide? The optic nerve conveys messages from the eye to the brain and enables you to see. In glaucoma, increased pressure in the eye damages the optic nerve, which can eventually lead to permanent vision loss, said Dr. Anoop Thomas, Principal Staff Physician at the Department of Ophthalmology and Visual Sciences at Khoo Teck Puat Hospital.
In Singapore, about 3 percent of the population above 40 years suffers from glaucoma. What’s more, the eye disease is seen more commonly in women, said Dr. Thomas. That’s because the prevalence of glaucoma increases with age, and women have an increased life expectancy.
Asians are at higher risk of primary angle-closure glaucoma, which typically affects smaller eyes. Women also generally have smaller eyes than men, which increases the risk for a subtype of the disease called angle-closure glaucoma, said Dr. Chua Wei Han, Medical Director and Senior Consultant Ophthalmologist at Mount Elizabeth Hospital.
GLAUCOMA IS A SILENT DISEASE
It’s important to note that most cases of glaucoma progress quietly until the disease reaches a very advanced stage, said Dr. Thomas. A person who has early glaucoma won’t be able to observe changes in their vision. Glaucoma causes the field of vision to become smaller, so as the disease progresses, the central vision used for reading and writing gets affected, leading to eventual blindness.
“The disease is silent in early stages as it mainly affects the peripheral vision (side vision of the eye), which means that the central vision used for reading and most other daily tasks are unaffected until the disease is advanced,” he explained. “Since the central vision is unaffected in the early stages, it is difficult for the patient to perceive that there is anything wrong with their vision.”
The exception is for patients diagnosed with acute angle-closure glaucoma, which happens when increased eye pressure rises quickly. They would experience headaches, eye redness, and blurred vision.
1. WHAT IS GLAUCOMA?
Glaucoma occurs when raised eye pressure causes direct damage to the optic nerve. Dr. Thomas explained that the increase in eye pressure first affects peripheral vision. As glaucoma progresses, it causes the field of vision to become “narrower,” eventually affecting the central vision and causing blindness.
There are two main types of glaucoma. In primary glaucoma, the disease is genetic in nature and arises due to genetic mutations, said Dr. Thomas. In secondary glaucoma, the disease happens due to other issues in the eye and body, such as eye trauma, inflammation, and eye complications from other medical conditions such as diabetes.
2. HOW IS GLAUCOMA DIAGNOSED?
It is diagnosed by an ophthalmologist through eye screening, where the eye specialist finds evidence of optic nerve damage. Both ophthalmologists and opticians use air puff tonometry (where a puff of air is blown to your eye) as a screening for elevated eye pressure. As glaucoma symptoms generally appear later in the course of the disease, going for eye screening is crucial.
But remember – as glaucoma symptoms generally appear later in the course of the disease, having no perceptible symptoms does not mean that the optic nerve is totally normal. “When blurry vision develops, the optic nerve damage is usually fairly advanced.” This is why eye screening is so crucial.
Also, as glaucoma is primarily a genetic disease, lifestyle modification – which is beneficial in diseases like diabetes and hypertension – doesn’t help. “Eating better, sleeping better, or exercising more will not affect the outcome of the disease,” Dr. Thomas explained.
He added that there is also “no robust evidence” that says that consuming nutritional supplements can prevent the onset or progression of glaucoma.
3. WHO IS AT RISK OF GLAUCOMA? IS IT HEREDITARY?
Primary glaucoma is genetic in nature, said Dr. Thomas, and therefore can run in families. His advice is to consider getting screened for it, especially if you are above 40 years of age, and if a close relative (your parents, siblings, or first cousin) has been diagnosed with glaucoma.
In addition to age and family history, Dr. Chua added that other risk factors include:
Dr. Chua recounted having a patient who developed glaucoma in both eyes when she was 24 years old. “Her main risk factor is high myopia, which in her case, was 2,500 degrees. Other common risk factors in younger people with glaucoma are use of steroids, eye trauma, or surgery,” he added.
4. CHRONIC KIDNEY DISEASE AND GLAUCOMA – WHAT IS THE LINK?
According to a local study released in June this year, researchers from the Yong Loo Lin School of Medicine at the National University of Singapore found that there was a bi-directional link between chronic kidney disease and glaucoma. This means you have a risk of glaucoma if you suffer from chronic kidney disease, and similarly, having chronic kidney disease puts you at risk of developing glaucoma.
The researchers found that:
5. WHILE GLAUCOMA SEEMS TO BE MORE COMMON IN OLDER WOMEN, CAN IT AFFECT WOMEN IN THEIR TWENTIES OR THIRTIES, TOO?
There are two types of primary glaucoma that affect younger people: congenital glaucoma and developmental glaucoma, which differ in age presentation, said Dr. Thomas. It's a spectrum, he added. Congenital glaucoma is when someone has the eye disease from birth, while developmental glaucoma presents during a person’s teen years to early adulthood and can be silent in the beginning, just like adult-onset glaucoma.
6. WILL I EVENTUALLY GO BLIND IF I HAVE GLAUCOMA?
It's a progressive eye condition that could lead to permanent vision loss if left untreated. “Any damage to the optic nerve and consequent visual impairment or blindness cannot be reversed or cured,” said Dr. Chua.
This is because “all current forms of treatment for glaucoma, be it medications or surgery, are aimed at lowering the intraocular (eye) pressure, which is a main risk factor for glaucoma.” The treatments either help to prevent the onset of glaucoma, such as nerve damage, or progression of glaucoma, which means further nerve damage. However, they cannot reverse any nerve damage, he explained.
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