01 Jan 2011
Fed up with the tedious rituals of the severely nearsighted – contact lenses, dry eyes and blind fumbling for glasses at night, Ms Frances Yap decided to go for LASIK.
However, at the last minute, her doctor called a stop to the procedure. She had developed a condition known as button hole (when the cornea’s curvature is irregular) which would have led to uneven vision after LASIK.
“He made the right decision in not going ahead with the procedure. But I was very disappointed,” she said.
That was three years ago, and she resigned herself to a lifetime of glasses and contact lenses. But early last year, Ms Yap’s husband persuaded her to see Professor Donald Tan, Medical Director, Singapore National Eye Centre (SNEC), after reading about the advances in vision correction Prof Tan and his team were making.
During her consultations with Prof Tan, Ms Yap, 32, found out that a new procedure could end her bespectacled days. In addition to being suitable for people with conditions such as buttonhole, the new procedure is very quick, painless and effectively corrects even high degrees of myopia.
Last March, Ms Yap became one of the first Singaporeans to undergo the procedure, known as ReLEx or Refractive Lenticule Extraction.
Unlike LASIK, which uses two lasers and vaporises the corneal tissue to correct vision, ReLEx uses only one laser for the entire procedure.
Instead of vaporising the unwanted tissue, the new generation of laser used in ReLEx simply cuts out a lens-shaped piece of corneal tissue to correct the myopia.
The tissue is extracted either through a regular flap as used in LASIK or through a keyhole incision, depending on the eye.
This means more accurate vision correction and less discomfort during and after surgery. “ReLEx is a natural progression from LASIK. ReLEx performs a very precise cut inside the cornea to laser out a lens shaped amount of tissue to match the degree. We then remove this lens and the myopia is gone,” said Prof Tan.
Excellent results
So far, the procedure has a 100 per cent success rate. It is also more accurate than LASIK, which is especially beneficial to those with higher degrees of myopia, between 500 and 1,000 degrees.
“This is currently the most advanced procedure available. And it only takes 30 seconds to perform the correction as this laser is extremely fast and uses very low energy, so there is less discomfort for patients,” said Prof Tan.
SNEC conducted a study of 24 patients who underwent LASIK and ReLEx (one procedure in each eye) and found that more than 75 per cent of them preferred ReLEx, as there’s less discomfort during and after surgery.
Another patient who has undergone ReLEx is Ms Gayathri Manokaran, a lab researcher who opted for this procedure to correct her mild myopia and astigmatism, so she could continue to pursue her new hobby – diving.
“I got my diver’s license recently, but it’s really quite futile if I can’t see underwater,” said the 31-year-old. “The procedure was so painless, I didn’t even realise it was over.”
ReLEx also feels more comfortable for the patient because the suction on the eye during the treatment is gentler.
“Patients are also able to see the ‘aiming beam’ better because of the gentle suction, so there is almost no occurrence of what doctors call ‘light blackout’ during the treatment as compared to LASIK,” said Prof Tan.
Light blackout is a phenomenon in which the laser beam the patient is told to focus on during the procedure vanishes when the patient moves his eye.
This temporary disappearance of the focal point can cause panic. However, the incidence of light blackout is dramatically reduced in ReLEx procedures.
The benefits of the new procedure are as clear as Ms Yap’s newly perfect vision.
“I don’t have to fumble for glasses when I wake up in the middle of the night to attend to my kids. It’s such a relief! You have no idea,” she said.
“I love to be able to dress up and leave the house without worrying about glasses or contact lenses,” added Ms Manokaran. What will then become of LASIK? As ReLEx becomes more widely used, it may eventually replace conventional LASIK.
“Over the years as we adopt new LASIK technology – just like Blackberry phone models – the results get better. And this is where ReLEx comes in – with it, patients now see even better,” said Prof Tan.
With wider use, the procedure will also become more affordable. Currently, ReLEx costs $2,500 per eye including post-operative care. Reversible treatment?
Cutting out an intact piece of corneal tissue has given researchers another idea – can this myopic lens be preserved and used later in a person’s life to correct presbyopia or long-sightedness?
“Let’s say, you get presbyopia later on in life after ReLEx. In theory, we can retrieve your stored myopic lens, laser away the surplus negative value on the lenses and place them back into your cornea to correct your presbyopia in one eye, essentially providing you with monovision, so one can see near again,” said Prof Tan.
A team of researchers at Singapore Eye Research Institute (SERI), the research arm of SNEC, is now looking at freezing and storing discarded lenses in liquid nitrogen, a method known as cryopreservation, commonly used for storing cord blood and stem cells.
So when presbyopia eventually occurs years later, a patient could choose to have his cut lens re-implanted into one of his corneas, to counteract the presbyopia and eliminate the need for reading glasses, or to modify refraction if it changes with time.
SERI researchers hope to prove the reversibility of ReLEx in initial trials, which started in late 2010.
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