You may not be too concerned about the vision loss from glaucoma when you’re young as it is commonly known to afflict seniors. Instead, you might pay more attention to myopia or short-sightedness. After all, Singapore is not known as the myopia capital of the world for nothing, when over 80 per cent of adults here are myopic.
But hold that thought because there is a link between the two eye conditions. In other words, having myopia now, especially severe myopia, may increase your risk of developing glaucoma later in life.
About 57,800 Singaporeans aged 60 years and above have glaucoma, according to NHG Eye Institute. This number is projected to rise by 43 per cent, reaching 85,800 by 2040.
Age certainly plays a part. “Glaucoma affects about 3 per cent of people above 40 years old,” said Dr Kenric Fan, an associate consultant with Singapore National Eye Centre’s Glaucoma Department. “It is around 10 per cent for patients above 70 years old”, although “we are diagnosing more patients in the community earlier due to patient education and screening efforts”.
Just what causes glaucoma and can the Lasik you’ve had affect your risk? Also, how effective is a new implant method that may lessen a life-long reliance on medicated eye drops for glaucoma patients?
Illustration showing how the excess fluid or aqueous humour exits the eye through the trabecular meshwork. (Art: iStock/Pikovit44)
Your body continually produces a plasma-like fluid (aka aqueous humour) in the eyeball to give it structure, nourishment and aid in waste removal. Normally, any overflow of this fluid is drained internally through the trabecular meshwork – a spongy ring structure located at an angle where the iris and the cornea meet – and into channels that collect the fluid before it is let into the bloodstream.
Things go awry when there is drainage inefficiency (more fluid is produced than drained) and pressure begins to build in the eye like a faulty air pump that won’t stop inflating the balloon. Rather than bursting, the increasing intraocular pressure damages the optic nerve, leading to permanent vision loss or what is known as glaucoma.
“There are two main types of glaucoma: open- and closed-angle glaucoma,” said Dr Fan. Open-angle glaucoma has no early symptoms, while the early symptoms for closed-angle glaucoma may be severe eye pain, acute eye redness, vision blurring, and an association with headache, nausea and vomiting, he said.
And because the more common form is open-angle glaucoma, the eye disease is often nicknamed “the silent thief of sight” because patients have no clear early symptoms, said Dr Fan.
(Art: iStock/petrroudny)
Myopia is a strong risk factor. For starters, myopic eyeballs are already stretched, making their optic nerves more fragile and susceptible to damage. “Weakness of the optic nerve as it enters the back of the eye is why there can be glaucomatous damage at relatively low pressures,” according to a study. In fact, said Dr Fan, “severe myopia (above 600 degrees) increases your life-time risk of glaucoma by about two to three times”.
The other risk factors, he added, include age, a family history, diabetes, trauma and the use of steroids. “Certain types of glaucoma are also associated with changes in our vascular system, such as having migraines, joint disorders and being female (for example, women’s hormonal changes and longer life expectancy can lead to a higher cumulative risk of age-related glaucoma).”
“Typical glaucoma usually affects both eyes but one eye may be more severe compared to the other,” said Dr Fan.
Unlike myopia, presbyopia doesn't directly cause or lead to glaucoma, according to this study. Both conditions may seem related as they often occur simultaneously after age 40. But while they share ageing-related changes in the eye's structure, such as the ciliary muscles, lens rigidity and fluid drainage, one does not cause the other.
Signs of glaucoma often start with a painless blurring of the peripheral or side vision. If you drive, you may notice that objects in the side mirror look blurry, or there may be small, dark spots marring your side vision. Patients may sometimes present with consistently red eyes.
As the disease progresses, you may find yourself bumping into objects because you can’t see them well. Your world would look dim and hazy as if you were wearing glasses with greasy lenses. Low-light conditions and the night would bring about rings or rainbows around bright lights.
At the advanced stage, you would have lost so much of your peripheral vision that everything looks like it’s seen through a tube or tunnel. But even that vision will go at the end stage, resulting in complete blindness. “It is important to highlight that the visual loss from glaucoma is irreversible,” highlighted Dr Fan.
“The most common laser treatment performed in Singapore is Lasik, which by itself, does not cause glaucoma,” said Dr Fan.
Implantable collamer lenses (ICLs) for correcting severe myopia, hyperopia and astigmatism, however, paint a slightly different picture. These corneal implants may be a contributing factor as they have been found to increase pressure in the eyeball in about 4.4 per cent of cases.
That could happen when the implants block fluid drainage in the eye; in one case, the blockage was caused by implants that were too large for the patient.
“ICLs do not directly cause glaucoma,” explained Dr Fan, “but they alter the fluid and spatial dynamics within the eye, which can then lead to a build-up of intraocular pressure.”
An implantable collamer lens or ICL. (Photo: iStock/Mohammed Al Ali)
One of the newer treatments for glaucoma is the PreserFlo MicroShunt. At SNEC, it has been performed on up to 1,000 patients since it was introduced at least five years ago. It has also been done at NHG Eye Institute since 2022 on close to 200 patients.
But how effective is it? That was what NHG Eye Institute set out to do with its recently completed study on the PreserFlo MicroShunt’s effectiveness in an Asian population. The study began in 2022 and followed 27 patients with primary open-angle glaucoma, who had undergone the procedure, for 24 months.
The researchers found that the average intraocular pressure reduced by 35 per cent from 22.1mmHg to 14.3mmHg (normal pressure ranges from 10mmHg to 21mmHg). “However, the target pressure varies for each patient based on the severity of their glaucoma,” said Dr Vivien Yip, who headed the study. She also leads Glaucoma & Comprehensive Eye Care Services at NHG Eye Institute.
Nearly half of the patients (48 per cent) were able to control their intraocular pressure without the need for medicated eye drops or further procedures after one year; that number dropped to 37 per cent in the second year, said Dr Yip.
An eyecare professional examines an image showing the back of the eye. (Photo: iStock/Goodboy Picture Company)
In 74 per cent of the patients in the first year, they managed to control their intraocular pressure post-PreserFlo MicroShunt with eye drops or stabilising injections. This form of success went down to 63 per cent in the following year.
Patients also took fewer glaucoma medications from an average point of 3.4 to 0.7 medications. “Although some patients still need eye drops for life, they are typically much fewer than before,” said Dr Yip. “In our study, the majority of patients was able to stop most or all of their glaucoma medications.”
Dr Yip admitted that there are several reasons why not everyone achieved or prolonged the success. “Glaucoma can be progressive, meaning it may worsen over time despite treatment; some patients' condition became more severe and needed additional treatment.”
And sometimes, she explained, “the body's natural healing process can cause scar tissue that reduces the implant's effectiveness”. “The important thing is that nearly two-thirds of patients had their eye pressure successfully controlled at two years, either with the surgery alone or with minimal additional treatment," she said.
Those with glaucoma may sometimes present with red eyes. (Photo: iStock/Werawad Ruangjaroon)
Of the 27 patients, Dr Yip shared that 17 also had cataract removal done in the same session. The study found that those who did the implantation alone achieved better long-term results than those who also had cataract removal in the same session, she said.
The micro shunt itself doesn’t require replacing. “It is designed to be a permanent implant made from durable biocompatible materials. In our 24-month study, none of the devices required replacement due to wear or deterioration,” said Dr Yip.
Still, despite the implant’s improvement rates on glaucoma, the condition cannot be reversed. “No surgery can reverse the damage that has occurred to the optic nerve,” qualified Dr Yip. “Surgery aims to preserve vision and improve quality of life of patients from the use of fewer medications.”
The insertion of a tiny, flexible shunt (8.5mm long and thinner than a hair strand) in front of the iris in each eye is performed with regional anaesthesia and moderate sedation, said Dr Yip. “Patients will feel some water washing their eye but otherwise, there is no pain or discomfort during surgery.”
It takes about one month for the wound to recover fully; in the meantime, vision is “usually the same or slightly blurred for the first few days but it recovers quickly”, said Dr Yip. “Some tearing may occur for the first few days due to the discomfort from the surgical wound but this will gradually lessen.”
Eye drops remain the first line of treatment for glaucoma. (Photo: iStock/bankerwin)
The PreserFlo Microshunt surgery is suitable for those whose glaucoma is not well controlled, despite using various types of eye drops and hitting the maximum number of eye drops that can be safely prescribed, said Dr Yip. “These are typically patients with primary open-angle glaucoma between ages 18 and 85, whose eye pressure remains high, even with multiple medications.
However, it is not for those with certain corneal conditions, specifically those with damaged or insufficient cells on the inner surface of the cornea, said Dr Yip. “Your eye specialist will assess whether you are a good candidate based on your specific situation, eye pressure levels and medical history.”
Eye drops (prostaglandin analogues, beta blockers, carbonic anhydrase inhibitors, alpha agonists and rho-kinase inhibitors) remain the first line of treatment for glaucoma, said Dr Fan, as they are easy to apply, non-invasive and affordable. “With good compliance and instillation techniques, they are effective at controlling glaucoma.”
Nonetheless, “each type of eye drop comes with its set of side effects, which are commonly eye irritation and eye redness; or seldom, systemic body side effects”, said Dr Fan.
Laser treatments such as selective laser trabeculoplasty (SLT), laser peripheral iridotomy (LPI) and transcyclophotocoagulation (TCP) are the other options available.
Get a comprehensive eye examination every one to two years, including an eye pressure check and optic nerve assessment. (Photo: iStock/Edwin Tan)
“SLT’s effectiveness is comparable to the initiation of one eye drop, and may be beneficial in younger patients or those with poorer access to medical facilities, given that eye drops commonly have to be applied for life,” said Dr Fan. Meanwhile, LPI and TCP are usually reserved for specific cases of closed-angle glaucoma and refractory glaucoma respectively, he said.
“Laser procedures are quick, cost effective and can reduce the need for long-term eye drops. However, their effects often diminish over time and may require repeat treatments or used in conjunction with eye drops,” said Dr Fan.
It’s not too late to watch out for glaucoma if you’re already in your 40s. Here are some tips from Dr Yip:
• Go for regular eye examinations: Get a comprehensive eye examination every one to two years, including an eye pressure check and optic nerve assessment. Those with risk factors may need more frequent screening.
• Know your risk factors: High-risk individuals include those with a family history of glaucoma, high eye pressure, steroid treatment, diabetes or severe myopia.
• Genetic counselling: Those with strong family histories can use genetic testing to help identify inherited risk factors and guide screening frequency.
• Maintain overall health: Managing conditions like diabetes and high blood pressure can help reduce glaucoma risk.
• Protect your eyes: Wear protective eyewear during sports and avoid eye injuries.
Continue reading...
But hold that thought because there is a link between the two eye conditions. In other words, having myopia now, especially severe myopia, may increase your risk of developing glaucoma later in life.
About 57,800 Singaporeans aged 60 years and above have glaucoma, according to NHG Eye Institute. This number is projected to rise by 43 per cent, reaching 85,800 by 2040.
Age certainly plays a part. “Glaucoma affects about 3 per cent of people above 40 years old,” said Dr Kenric Fan, an associate consultant with Singapore National Eye Centre’s Glaucoma Department. “It is around 10 per cent for patients above 70 years old”, although “we are diagnosing more patients in the community earlier due to patient education and screening efforts”.
Just what causes glaucoma and can the Lasik you’ve had affect your risk? Also, how effective is a new implant method that may lessen a life-long reliance on medicated eye drops for glaucoma patients?
HOW DOES GLAUCOMA ARISE IN THE FIRST PLACE?
Illustration showing how the excess fluid or aqueous humour exits the eye through the trabecular meshwork. (Art: iStock/Pikovit44)
Your body continually produces a plasma-like fluid (aka aqueous humour) in the eyeball to give it structure, nourishment and aid in waste removal. Normally, any overflow of this fluid is drained internally through the trabecular meshwork – a spongy ring structure located at an angle where the iris and the cornea meet – and into channels that collect the fluid before it is let into the bloodstream.
Things go awry when there is drainage inefficiency (more fluid is produced than drained) and pressure begins to build in the eye like a faulty air pump that won’t stop inflating the balloon. Rather than bursting, the increasing intraocular pressure damages the optic nerve, leading to permanent vision loss or what is known as glaucoma.
“There are two main types of glaucoma: open- and closed-angle glaucoma,” said Dr Fan. Open-angle glaucoma has no early symptoms, while the early symptoms for closed-angle glaucoma may be severe eye pain, acute eye redness, vision blurring, and an association with headache, nausea and vomiting, he said.
And because the more common form is open-angle glaucoma, the eye disease is often nicknamed “the silent thief of sight” because patients have no clear early symptoms, said Dr Fan.
(Art: iStock/petrroudny)
WHAT ARE THE CAUSES?
Myopia is a strong risk factor. For starters, myopic eyeballs are already stretched, making their optic nerves more fragile and susceptible to damage. “Weakness of the optic nerve as it enters the back of the eye is why there can be glaucomatous damage at relatively low pressures,” according to a study. In fact, said Dr Fan, “severe myopia (above 600 degrees) increases your life-time risk of glaucoma by about two to three times”.
The other risk factors, he added, include age, a family history, diabetes, trauma and the use of steroids. “Certain types of glaucoma are also associated with changes in our vascular system, such as having migraines, joint disorders and being female (for example, women’s hormonal changes and longer life expectancy can lead to a higher cumulative risk of age-related glaucoma).”
“Typical glaucoma usually affects both eyes but one eye may be more severe compared to the other,” said Dr Fan.
Unlike myopia, presbyopia doesn't directly cause or lead to glaucoma, according to this study. Both conditions may seem related as they often occur simultaneously after age 40. But while they share ageing-related changes in the eye's structure, such as the ciliary muscles, lens rigidity and fluid drainage, one does not cause the other.
WHAT IS THE VISION OF SOMEONE WITH GLAUCOMA?
Signs of glaucoma often start with a painless blurring of the peripheral or side vision. If you drive, you may notice that objects in the side mirror look blurry, or there may be small, dark spots marring your side vision. Patients may sometimes present with consistently red eyes.
As the disease progresses, you may find yourself bumping into objects because you can’t see them well. Your world would look dim and hazy as if you were wearing glasses with greasy lenses. Low-light conditions and the night would bring about rings or rainbows around bright lights.
At the advanced stage, you would have lost so much of your peripheral vision that everything looks like it’s seen through a tube or tunnel. But even that vision will go at the end stage, resulting in complete blindness. “It is important to highlight that the visual loss from glaucoma is irreversible,” highlighted Dr Fan.
WOULD HAVING LASIK AND CORNEAL IMPLANTS INCREASE YOUR RISK?
“The most common laser treatment performed in Singapore is Lasik, which by itself, does not cause glaucoma,” said Dr Fan.
Implantable collamer lenses (ICLs) for correcting severe myopia, hyperopia and astigmatism, however, paint a slightly different picture. These corneal implants may be a contributing factor as they have been found to increase pressure in the eyeball in about 4.4 per cent of cases.
That could happen when the implants block fluid drainage in the eye; in one case, the blockage was caused by implants that were too large for the patient.
“ICLs do not directly cause glaucoma,” explained Dr Fan, “but they alter the fluid and spatial dynamics within the eye, which can then lead to a build-up of intraocular pressure.”
An implantable collamer lens or ICL. (Photo: iStock/Mohammed Al Ali)
WHAT ARE THE TREATMENTS AVAILABLE?
One of the newer treatments for glaucoma is the PreserFlo MicroShunt. At SNEC, it has been performed on up to 1,000 patients since it was introduced at least five years ago. It has also been done at NHG Eye Institute since 2022 on close to 200 patients.
But how effective is it? That was what NHG Eye Institute set out to do with its recently completed study on the PreserFlo MicroShunt’s effectiveness in an Asian population. The study began in 2022 and followed 27 patients with primary open-angle glaucoma, who had undergone the procedure, for 24 months.
The researchers found that the average intraocular pressure reduced by 35 per cent from 22.1mmHg to 14.3mmHg (normal pressure ranges from 10mmHg to 21mmHg). “However, the target pressure varies for each patient based on the severity of their glaucoma,” said Dr Vivien Yip, who headed the study. She also leads Glaucoma & Comprehensive Eye Care Services at NHG Eye Institute.
Nearly half of the patients (48 per cent) were able to control their intraocular pressure without the need for medicated eye drops or further procedures after one year; that number dropped to 37 per cent in the second year, said Dr Yip.
An eyecare professional examines an image showing the back of the eye. (Photo: iStock/Goodboy Picture Company)
In 74 per cent of the patients in the first year, they managed to control their intraocular pressure post-PreserFlo MicroShunt with eye drops or stabilising injections. This form of success went down to 63 per cent in the following year.
Patients also took fewer glaucoma medications from an average point of 3.4 to 0.7 medications. “Although some patients still need eye drops for life, they are typically much fewer than before,” said Dr Yip. “In our study, the majority of patients was able to stop most or all of their glaucoma medications.”
Dr Yip admitted that there are several reasons why not everyone achieved or prolonged the success. “Glaucoma can be progressive, meaning it may worsen over time despite treatment; some patients' condition became more severe and needed additional treatment.”
And sometimes, she explained, “the body's natural healing process can cause scar tissue that reduces the implant's effectiveness”. “The important thing is that nearly two-thirds of patients had their eye pressure successfully controlled at two years, either with the surgery alone or with minimal additional treatment," she said.
Those with glaucoma may sometimes present with red eyes. (Photo: iStock/Werawad Ruangjaroon)
Of the 27 patients, Dr Yip shared that 17 also had cataract removal done in the same session. The study found that those who did the implantation alone achieved better long-term results than those who also had cataract removal in the same session, she said.
The micro shunt itself doesn’t require replacing. “It is designed to be a permanent implant made from durable biocompatible materials. In our 24-month study, none of the devices required replacement due to wear or deterioration,” said Dr Yip.
Still, despite the implant’s improvement rates on glaucoma, the condition cannot be reversed. “No surgery can reverse the damage that has occurred to the optic nerve,” qualified Dr Yip. “Surgery aims to preserve vision and improve quality of life of patients from the use of fewer medications.”
WHAT DOES THE SHUNT IMPLANT PROCEDURE INVOLVE? WHO IS SUITABLE?
The insertion of a tiny, flexible shunt (8.5mm long and thinner than a hair strand) in front of the iris in each eye is performed with regional anaesthesia and moderate sedation, said Dr Yip. “Patients will feel some water washing their eye but otherwise, there is no pain or discomfort during surgery.”
It takes about one month for the wound to recover fully; in the meantime, vision is “usually the same or slightly blurred for the first few days but it recovers quickly”, said Dr Yip. “Some tearing may occur for the first few days due to the discomfort from the surgical wound but this will gradually lessen.”
Eye drops remain the first line of treatment for glaucoma. (Photo: iStock/bankerwin)
The PreserFlo Microshunt surgery is suitable for those whose glaucoma is not well controlled, despite using various types of eye drops and hitting the maximum number of eye drops that can be safely prescribed, said Dr Yip. “These are typically patients with primary open-angle glaucoma between ages 18 and 85, whose eye pressure remains high, even with multiple medications.
However, it is not for those with certain corneal conditions, specifically those with damaged or insufficient cells on the inner surface of the cornea, said Dr Yip. “Your eye specialist will assess whether you are a good candidate based on your specific situation, eye pressure levels and medical history.”
WHAT ELSE IS USED TO CONTROL GLAUCOMA?
Eye drops (prostaglandin analogues, beta blockers, carbonic anhydrase inhibitors, alpha agonists and rho-kinase inhibitors) remain the first line of treatment for glaucoma, said Dr Fan, as they are easy to apply, non-invasive and affordable. “With good compliance and instillation techniques, they are effective at controlling glaucoma.”
Nonetheless, “each type of eye drop comes with its set of side effects, which are commonly eye irritation and eye redness; or seldom, systemic body side effects”, said Dr Fan.
Laser treatments such as selective laser trabeculoplasty (SLT), laser peripheral iridotomy (LPI) and transcyclophotocoagulation (TCP) are the other options available.
Get a comprehensive eye examination every one to two years, including an eye pressure check and optic nerve assessment. (Photo: iStock/Edwin Tan)
“SLT’s effectiveness is comparable to the initiation of one eye drop, and may be beneficial in younger patients or those with poorer access to medical facilities, given that eye drops commonly have to be applied for life,” said Dr Fan. Meanwhile, LPI and TCP are usually reserved for specific cases of closed-angle glaucoma and refractory glaucoma respectively, he said.
“Laser procedures are quick, cost effective and can reduce the need for long-term eye drops. However, their effects often diminish over time and may require repeat treatments or used in conjunction with eye drops,” said Dr Fan.
WHAT CAN BE DONE TO PREVENT GLAUCOMA?
It’s not too late to watch out for glaucoma if you’re already in your 40s. Here are some tips from Dr Yip:
• Go for regular eye examinations: Get a comprehensive eye examination every one to two years, including an eye pressure check and optic nerve assessment. Those with risk factors may need more frequent screening.
• Know your risk factors: High-risk individuals include those with a family history of glaucoma, high eye pressure, steroid treatment, diabetes or severe myopia.
• Genetic counselling: Those with strong family histories can use genetic testing to help identify inherited risk factors and guide screening frequency.
• Maintain overall health: Managing conditions like diabetes and high blood pressure can help reduce glaucoma risk.
• Protect your eyes: Wear protective eyewear during sports and avoid eye injuries.
Continue reading...