SINGAPORE – Ms Candice Chong started wearing glasses when she was four.
By the time she was 13, she had a lens prescription of around minus 10 dioptres (1,000 degrees) for each eye, and her myopia continued to worsen throughout her teenage years to reach around 2,000 degrees in each eye.
High myopia is typically defined as short-sightedness of over minus 5 dioptres (500 degrees), though some experts argue that it should be minus 6 dioptres (600 degrees) and above.
Excessive eye growth, or elongation of the eyeball, causes myopia. In some cases, myopes like Ms Chong, now 43, suffer from pathologic myopia, which in turn causes degenerative changes to the back of the eye.
“Normal eyeballs are like fishballs, but for people like me, my eyeballs are the shape of a sausage... very stretched, elongated... and more fragile overall,” said Ms Chong.
She started experiencing complications due to her high myopia not long after she turned 20.
First, it was glaucoma. Then, she had cataract surgery in one eye, and then the other, in her 30s. In 2023, she underwent surgery to prevent a retinal tear in her left eye.
Singapore is seeing more and more highly myopic adults, and the number is expected to grow in the coming decades.
“We cannot see the problem now, but it will come,” said Professor Saw Seang Mei, the Distinguished Wallace Foulds Professor at Duke-NUS Medical School.
“Pathologic myopia, a rising problem, will be a leading cause of low vision in Singapore in the next few years.”
Prof Saw, who is also co-head of the myopia research group at the Singapore Eye Research Institute (Seri), has projected that the number of myopic adults aged 50 and above in Singapore will rise from 40 per cent of that segment of the population currently to 80 per cent in the next few decades.
This is because the older adults of the near future will have had, when they were children, a lifestyle conducive to the development of myopia – more reading and writing, and more time spent in front of screens rather than outdoors.
Similarly, high myopia in older adults will also be more prevalent and afflict 15 per cent of Singapore’s population in the coming decades, up from 6 per cent today, while pathologic myopia rates will climb from 4 per cent to 10 per cent, she said.
There are two million myopic adults and 350,000 highly myopic adults among Singapore residents today.
The Singapore National Eye Centre (SNEC) is already seeing rising numbers of patients with high myopia.
Associate Professor Donny Hoang arrived in Singapore from New York to start a high myopia clinic at SNEC in 2017.
In that first year, he saw 119 patients, he said.
By June 2024, as awareness of high myopia has grown, he had seen 2,125 high myopia patients in total.
“In New York, I looked for five years and I found 50 (high myopia) patients in Columbia University. And then, I moved here and in two years, I already had 1,000 patients that I am following,” he said.
Prof Hoang, a senior consultant in the surgical retinal department and myopia centre at SNEC focusing on high and pathologic myopia, was previously director of the High Myopia Laboratory at Columbia University in New York City.
He said the greatest visual threats to high myopia patients are the development of pathologic myopia and permanent vision loss from conditions such as glaucoma and myopic macular degeneration.
“If the eye wall is strong, even if it is a long eye, it is less likely to have all these problems,” said Prof Hoang.
But if it resembles “a very overinflated balloon with a very thin wall”, he added, the eye is likely to bulge out more, bleed, and have cracks in the wall and splitting of the retina layers, which is what happens in pathologic myopia.
At the SNEC high myopia clinic, nearly 90 per cent of the patients developed deformation of the eye wall (posterior staphyloma) or thinning of the retina (myopic macular degeneration), and some had bleeding inside the eye. Their average age is 64 and more than half of them are women.
“The younger you start becoming myopic, the higher the end point you’re going to reach in terms of your degrees, because your eyes stop growing when you stop growing,” said Prof Hoang, who is also the deputy head of the Myopia Unit at Seri.
“So when you’re 22 or 23, you’re not really getting any taller, so your eyes should not be getting much longer either.”
The more severe the myopia, the more likely a highly myopic adult will develop pathologic myopia. The risk also increases as highly myopic adults age, with research done here showing that the progression to more severe forms of pathologic myopia is much worse after 70 years of age, Prof Saw said.
At least two out of three highly myopic adults will develop pathologic myopia by the age of 70. Almost all older adults with extreme myopia of worse than 12 dioptres (1,200 degrees) will develop pathologic myopia when they reach 80 or 90 years of age, she said.
The numbers are based on an ongoing population study on the impact of high myopia in Singapore known as the Singapore Epidemiology of Eye Diseases (Seed) High Myopia study, for which Prof Saw is the principal investigator.
At the 12-year follow-up mark of the Seed study, the adults with pathologic myopia saw their condition getting worse, with more developing low vision, she said.
At 43, Ms Chong is already preparing herself for further vision impairment. Six years ago, she started to notice changes in her vision.
“If you go for a holiday in the mountains and see the misty, cloudy skies, that’s what I see. My world is eternally foggy,” she said.
“My condition is degenerative... As my eyesight gets more foggy, I will have to be more careful moving around at night. I’ve tripped because I thought the ground was even when it was not... I’ve collided into pillars, glass.”
When she was a student, Ms Chong went to optical shops to get her glasses and lenses, and did not notice anything was amiss until she decided to go for Lasik surgery in her 20s.
She said she had to first undergo a lens implant, and that was when the surgeon noticed that her eye pressure was a little high and referred her to a glaucoma specialist.
The Lasik surgery was never done.
But even if she had gone through with it, she would still have the same issues; the eye complications of high myopia are related to changes in the structure of the eyeball and cannot be corrected by glasses, Lasik or cataract surgery.
“I am handicapped in some ways already. If you have a family history of high myopia, it is important to get checked. If you don’t, eye care is still important. Take vision breaks and don’t look at your phone in the dark,” she said.
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Some of Ms Chong’s family members have pathologic myopia. Her aunt has had surgery after experiencing retinal detachment. And in 2023, her uncle with high myopia accidentally collided with his friend’s head in the pool while swimming and suffered a retinal tear.
“Retinal detachment doesn’t just happen to lau pok (Hokkien for lousy) eyes like mine, it can happen to others... So if you start to see flashes, floaters, and you notice that your vision is not normal, go to A&E straight away,” she said.
Prof Hoang said these are not the usual few floaters people sometimes experience, but dots or specks that are so numerous they cannot be counted, and are accompanied by flashing lights that are like a lightning storm taking place in the eye.
For highly myopic people, flashes and floaters could point to a retinal tear, but there are other threats to vision, including bleeding, to look out for.
Prof Hoang asks his patients to cover one eye and look at the same object – maybe a door or window frame – from the same distance every day, and see if it appears crooked or wavy. If so, they should check again two hours later. If it is still crooked, he wants to see them within a day or two.
At SNEC, most of Prof Hoang’s patients have a refractive error of 1,500-3,000 degrees in their eyes; some are already legally blind in one eye.
“The biggest misconception of the people that I see is that they think, ‘oh, my degree is over 1,000 or 1,500. It just means I need Lasik earlier, I need thicker spectacles, I need to wear contact lenses that are thicker’... but they are not aware of the fact that suddenly they’re at much higher risk of these potentially blinding problems,” said Prof Hoang.
To prevent myopia, young children should spend more time outdoors in natural light and limit the time spent on near work – activities requiring a short working distance for the eyes, such as looking at screens, reading and doing craft work with small objects.
If the child is already myopic and the myopia is progressing fast, see an eye care practitioner for treatment, such as atropine eye drops, to prevent them from getting high myopia, Prof Hoang said.
Adults with high myopia should go for a comprehensive eye screening to check for glaucoma and other possible complications. Those with extreme myopia of 1,000 degrees or more should get screened earlier, from the age of 40, he said.
This article was first published in The Straits Times. Permission required for reproduction.
