Thursday, December 9, 2010

Are you seeing this?

Don't overlook the danger

SINGAPORE - Singapore is recognised for several things - the unparalleled efficiency of our airport, the sheer variety of food, leisure and entertainment options, among other things.

Good points aside, our little red dot is also well known for having the highest prevalence of myopia around the world.

At the age of seven, 20 per cent of Singapore children are myopic, said Dr Leonard Ang, the medical director of The Eye and Cornea Transplant Centre and Premium Lasik Surgery Clinic. By the time they reach about 20, the figure soars to more than 70 per cent.

The statistics are worrying, said US-based myopia researcher Dr Earl Smith, who was in town last month for the National Congress of Optometry and Opticianry, where he spoke about treatment strategies for myopia.

Dr Smith, who is the dean of the College of Optometry at the University of Houston, sees Singapore's high myopia rate as a "serious public health issue".

More worryingly is that, these days, myopia has become so common that no one bats an eyelid whenever a child is diagnosed with the condition.

The risks of high myopia

"People often think nearsightedness is not an important condition, because it can be easily corrected with contact lenses or spectacles," said Dr Smith.

However, he added that the abnormal structural changes that occur in the myopic eye put it at a higher risk of developing other blinding conditions such as glaucoma.

According to Dr Ang, those with high myopia - nearsightedness of more than 600 degrees - have a higher risk of such complications. Among myopic adults in Singapore, 10 per cent have high myopia.

Other potential blinding problems include macular degeneration and retinal detachment, where the innermost nerve layer of the eye detaches, said Dr Ang. Cataract, which is commonly associated with ageing, can also occur at a younger age if you have high myopia.

Don't just blame your genes

Eye researchers once believed that a person's genetic makeup is to blame. However, Dr Smith said it is not as simple.

"If you look at the dramatic increase in myopia rates over the last 30 years in Singapore, that is something which cannot be explained by bad genes. Clearly, there is an environmental trigger," he rationalised.

Urbanisation has been strongly associated with myopia. "Studies show that outdoor activities have strong protective effects against myopia," said Dr Smith.

"Singapore children are schooled early, and a dense population means limited outdoor space. Include genetic bias (towards developing myopia), that's three strikes against you," he said.

Conventional specs worsen myopia?

Dr Smith's new research also suggests that conventional spectacles may "worsen the progression of myopia".

Traditionally, corrective spectacle lenses help bring distant objects into focus. However, these lenses only correct the central vision, ignoring peripheral vision.

According to Dr Smith's study findings, peripheral retinal image plays a major role in influencing eye growth and myopia. He added that using lenses that correct peripheral optical errors may help to control myopia progression.

However, Dr Ang said that this is a "postulation". Currently, there is no cure for myopia.

Most treatments aimed at retarding myopia progression only have temporary results.

"Many believe that myopia is multi-factorial and other factors may also influence its progression. At present, there is no single method that is proven to be very effective and safe in the long-term," said Dr Ang.

Some methods used to delay myopia progression in your child
Dr Leonard Ang talks about some of the methods available to delay its progression.

Progressive (multifocal) spectacles

- This method uses two focal points, introducing an optical error that is believed to slow eyeball growth. However, there is currently no conclusive evidence on its effectiveness.

Atrophine eyedrops

- Eye drops are used to dilate the pupils. There have been some promising results but the reduction of myopia is minimal. The results may also be reversed when the child stops using the eye drops. There may also be long and short-term side effects.

Orthokeratology (corneal reshaping)

- This is a controversial, non-surgical treatment which consists of fitting a series of rigid gas-permeable lenses to modify the shape of the cornea to try retard myopia progression. The lenses are worn overnight, so serious complications like infections may occur, and this can lead to permanent vision loss.

- TODAY/rl

Taken from; source article is below:
Don't overlook the danger

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