An invisible disease

Annual check-up and screenings could thwart glaucoma's progression, says eye specialist

Nicknamed "the silent thief of sight", glaucoma gradually and painlessly robs patients of their ability to see. With no early warning signs, the eye disease is in fact preventable only by means of a comprehensive eye examination.

Speaking to mark the World Glaucoma Week -- observed annually from March 12 to 18 -- Assoc Prof Dr Manchima Makornwattana of the Thai Glaucoma Society encourages people aged above 40 to screen for glaucoma at least once a year.

"That's the message that not just the Thai Glaucoma Society but also the World Glaucoma Association always want to emphasise. Eye health is something we often overlook. As long as we can still see things, we think there's no problem. There is also a misconception that eye diseases only attack old people. We are wrong," said Dr Manchima, glaucoma and cataract specialist and also CEO of Ruxta Eye Centre.

Glaucoma is a disease that damages the eye's optic nerve. According to Dr Manchima, it is found in 1% of people aged above 60 and 5% of those over 40 years old. Though glaucoma is worrisome because it usually has no symptoms until it reaches severe stages, it is actually not responsible for most blindness cases around the world. Rather Aged-Related Macular Degeneration (AMD) is the leading cause of vision loss -- more than cataracts and glaucoma combined -- according to the American Macular Degeneration Foundation. Macular Degeneration is caused by the deterioration of the central portion of the retina. It's incurable and unstoppable.

Glaucoma is generally caused by a failure of the eye to maintain an appropriate balance between the amount of internal eye fluid produced and the amount that drains away, explained Dr Manchima. The fluid drains out through an area called the drainage angle. If this area does not function properly, fluids in the eye build up, causing pressure inside the eye to rise. This subsequently damages the optic nerves. Once these optic nerves die, patients will start to develop blind spots in their vision.

These blind spots are hardly noticeable until a large number of optic nerves are destroyed. And here Dr Manchima made an analogy between the eye's function and a garment factory.

"Imagine you have a factory producing clothes," she said. "You have 100 workers who make 100 shirts every day. Once the number of workers are down to 50, they might still be able to make 100 shirts. But here you fail to check how many workers you actually have. Until one day your staff produces less shirts, then you start to realise what's wrong with them, which by then might be too late."

And doctors, unfortunately, cannot bring back those damaged optic nerves, she added. They can only maintain the health of the remaining ones. "This is why glaucoma should better be detected at an early stage. If we can stop further damage, patients are likely to be able to see for the rest of their lives."

Glaucoma is in most cases genetic especially among first-degree relatives, meaning one's offspring, siblings and parents, Dr Manchima said. If one of your first-degree relatives have glaucoma, chances that you will fall prey to the eye disease are 5-8% higher than normal people.

People with high degree of short-sightedness or more than -600 and high degree of far-sightedness or more than +200 to +300 are at a higher risk of developing glaucoma, the eye specialist added. Patients who regularly take certain types of medication, especially steroids, are highly likely to suffer glaucoma given these drugs are reported to elevate eye pressure.

"Glaucoma patients will also suffer visual field defects, which means they will not have a clear vision on the left and right of their eyes. These people might find themselves having more accidents. When something is thrown at them from the left, for instance, they will not see it and will only know it once the object hits the head."

But even though the lost vision cannot be regained, eye doctors can stop further damage of the optic nerves if the disease is detected fast enough. Treatments include an eye drop to lower eye pressure and laser treatments to help with eye fluid drainage, as well as surgery. All this is to stop the abnormality in the eye from deteriorating.

"Technologies to treat glaucoma have greatly developed during the past decade. Ten years ago, many cases of glaucoma might end up in blindness. Today it is not like that. Some patients might still lose their vision but such a case is rare, thanks to medical innovations," commented Dr Manchima, adding that the regeneration and transplantation of optic nerves to restore vision is currently in the development phase so this method is yet to be used as a cure for glaucoma.

An eye check-up is consequently the best prevention against glaucoma but this should be carried out by an ophthalmologist to first check the eye pressure. Additional tests might be prescribed in case some abnormalities are detected. Eyesight measurement alone cannot screen for glaucoma.

"People aged above 40 should have a thorough eye exam at least once a year to check for risks. This is the best medicine for glaucoma, which can also prevent the country from having to spend its resources taking care of people blinded by the disease. The ability to see is most important. Everybody wants to wake up and be able to differentiate between day and night. And therefore eye health must never be overlooked."

Ruxta Eye Centre at Life Centre on Sathon Road offers free eye check-ups for 50 people this month. This includes tests for visual acuity, auto refraction, colour vision, eye pressure and slit-lamp exams to screen for glaucoma. For registration, call 061-590-5599.


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