‘Braces for the eyes’
SINGAPORE — At the age of 14, Ms Goh Jia Ling was already wearing spectacles with a prescription of around 800 degrees. The Raffles Institute student’s heavy glasses got in the way of badminton training. Soft contact lenses were equally uncomfortable, as they made her eyes dry.
Two years ago, Ms Goh switched to orthokeratology, otherwise known as ortho-k. She now wears specially designed cornea moulds, which look like hard lenses, to sleep every night.
The lenses reshape her corneas and by the time she removes them in the morning, she can see clearly without her glasses.
FOR HIGHER DEGREES NOW
Myopia, or short-sightendness, occurs when the eyeball is too long, causing light to fall in front of the retina rather than on it. This causes distant objects to appear blurred.
Singapore has the highest myopia rate in the world. About 80 per cent of 18-year-olds grapple with the condition, says the Singapore National Eye Centre (SNEC).
Optometrist and orthokeratologist Titus Wu, of Titus Eye Care, described the ortho-k treatment as “braces for the eyes”.
Dr Stan Isaacs, president of the Singapore Contact Lens Society and the Society of Orthokeratology, Singapore, said the method can also be used to correct long-sightedness and astigmatism.
Previously, ortho-k lenses could correct myopia of only up to 500 degrees, which meant patients like Ms Goh would have had to correct her remaining 300 degrees using either spectacles or contact lenses, said Mr Wu, who is a fellow in the International Academy of Orthokeratology.
New technology now allows those with up to 1,200 degrees of myopia to use the lenses, which can last for about two years. They cost from S$1,800 to over S$3,000, said Mr Wu.
While ortho-k has been available for decades here, Dr Isaacs said it is not widely publicised in Singapore as there are few qualified orthokeratologists here. Legally, local contact lens practitioners can supply and fit ortho-k lenses. However, Dr Isaacs said, most ortho-k manufacturers require practitioners to undergo certifying courses or workshops.
The treatment is suitable for all ages. In Asia, it is mostly used on children to control myopia progression, said Dr Isaacs.
Mr Wu said children from as young as six years old can use ortho-k. Primary and secondary school students are good candidates as they experience the highest myopia progression, an average increase of about 75 degrees per year. He said research has shown that ortho-k is “one of the most effective methods for myopia control”, doing so by reducing eyeball growth.
ORTHO-K VERSUS LASIK
Lasik surgery, which surgically and permanently reshapes the cornea, is generally not recommended for children and teens. This is because childhood myopia usually continues to progress and only stabilises at around the age of 21, said Mr Wu.
Unlike Lasik, ortho-k is not a permanent treatment for myopia, said Professor Donald Tan, senior consultant ophthalmologist at the Corneal and External Eye Disease Department at SNEC, and Arthur Lim Professor in Ophthalmology at SNEC.
The clear vision typically lasts about 18 hours after the lenses are taken out, but can vary between 12 to 48 hours, said Mr Wu.
Said Ms Goh: “There were times I forgot to wear them at night but I could still see quite clearly the next day. The effect doesn’t wear off so quickly.”
UNDERSTANDING THE RISKS INVOLVED
Dr Loh Boon Kwang, an ophthalmologist at Gleneagles Hospital, Singapore, has encountered a primary school student whose corneal infection from wearing ortho-k lenses was so serious, he required hospitalisation and intensive treatment.
In 2007, SNEC saw five children between the ages of nine and 14 with severe corneal infections linked to the use of overnight ortho-k lenses.
“Although most of them were treated successfully with antibiotic eye drops, all ended up with corneal scarring and some degree of visual loss,” said Prof Tan.
Corneal abrasions may occur when the lenses are not properly cleaned and particles rub against the cornea, said Dr Loh. The lenses may also rub against the cornea and lead to infection that may affect vision permanently, he said.
Studies reviewing the safety of ortho-k lens use had varying results. Prof Tan said a 2013 study in the United States found that the infection risk in children using them is 0.139 per cent, similar to the risk level adults face when wearing soft contact lenses overnight.
On the other hand, ortho-k practitioners say that as long as users are fitted by trained practitioners and follow proper instructions, infection risks are low.
In an American Journal of Optometry study, the infection rate from ortho-k lens wear was 0.077 per cent, a rate that might be lower than some forms of contact lens use, said Mr Wu.
“The ortho-k lenses used in Singapore are approved by the US Food and Drug Administration for overnight wear, and have been proven to allow the eyes to breathe as much as when the lenses are not worn,” said Mr Wu.
OPTIONS AND SIGNS
Ultimately, parents need to be aware of the potential risks of severe corneal infections linked to ortho-k lens use, and weigh its pros and cons, said Prof Tan.
Parents should also be aware of alternatives to slow down myopia progression, such as the use of low-dose atropine eye drops, said Prof Tan.
For parents whose children are using ortho-k lenses, they should keep an eye on the warning signs.
“If a child experiences pain, discomfort, tearing, eye discharge, eye redness or sudden blurring of vision, seek immediate examination by the optometrist who fitted the lenses. Early referral to an ophthalmologist to diagnose and treat any infection is important,” said Prof Tan.
Control myopia with good eye habits
- When reading, keep your book 30cm away from the eyes.
- Read in a well-lit environment.
- Sit up to read. Do not read while lying down.
- Reduce unnecessary near-sighted work on the computer and handheld devices.
- Rest the eyes after 30 minutes of reading.
- Engage in outdoor activities regularly every week.
Source: Dr Loh Boon Kwang, ophthalmologist at Gleneagles