Age-related macular degeneration is the second leading cause of blindness in the world. Now, there's another treatment for it.
PENANG, Malaysia (The Star), November 18, 2007:
The word “degeneration” is the kind of word often used with an air of quiet depression.
Not for Mary Ann Leong. At age 62, Mary Ann is a voracious reader and a proud grandmother of four grandchildren. About four years ago, Mary Ann was diagnosed with age-related macular degeneration (AMD).
Mary Ann Leong ... 'I first noticed distortions (visual) in the right eye, and then it affected my left eye.” AMD is a degenerative eye disease, which normally affects people over the age of 50. It affects the macula region in the inner layer of the eye (retina), which is responsible for central vision.
“It started suddenly in January 2004. I first noticed distortions (of my eyesight) in the right eye, and then it affected my left eye,” Mary Ann said.
“I was a passenger in a car, when I noticed the yellow line on the road was wavy. I closed one eye (right eye), and the lines were straight again; then I closed the other eye, the lines appeared wavy.”
Experiencing vision loss may have been traumatic to most people, but Mary Ann took her condition with a pinch of salt and lots of humour.
“During my free time, I still listen to music, read, walk and go to the gym.” she said. “When it (AMD) is not severe, the waves are small. When it is more severe, the waves are like an ECG – they go 'beep, beep'.”
What Mary Ann is experiencing is an advanced form of AMD, and she is not alone. Advanced AMD is estimated to affect 25-30 million people worldwide. In Malaysia, it is estimated that this disease will affect three to four out of a hundred people over the age of 50 years.
Age related macular degeneration (AMD)
AMD is a medical condition where degeneration or damage occurs in the light-sensitive cells in the macula (the area that controls central vision), which is located at the inner layer of the eye (retina).
Ranking second in the leading causes of blindness, AMD is a silent thief that slowly robs patients of their sight. There are two kinds of AMD, dry AMD and wet AMD. Dry AMD is the degeneration of the cells in the retina. Wet AMD is caused by the growth of new blood vessels underneath the layer (choroidal neovascularisation, CNV), causing distortion and damage to the retina.
“Imagine wearing a pair of glasses with a dark smudge right in the middle of the lens. This is what a person suffering from AMD sees,” Prof Dr Che Muhaya Mohamad, Chairman of the Malaysian Medical Association (MMA) Ophthalmological Society said, describing events that occur when you have wet AMD.
“With this image in mind, now try to imagine fulfilling day-to-day tasks like reading, driving or simply being able to recognise a friend's face,” she explained. Wet AMD needs to be treated early, as it can cause sudden and permanent vision loss if not treated in a timely manner.
You know you may have AMD when ...
Consultant ophthalmologist Dr Wong Jun Shyan ... ‘The only downside is its high cost.You are more than 50, and experiencing sudden or progressive deterioration of sight. Straight lines may seem wavy and your vision starts to blur. You see objects like the screen of a black-and-white TV, with washed out colours and grainy pictures. Suddenly, there is a patch of grey blocking the view in the centre of one or both of your eyes; no matter how much you rub, it doesn't go away.
“It is sad that most people think visual loss is something natural (in ageing), which is why they complain to a doctor fairly late,” Prof Dr Che Muhaya said.
The screening test for AMD is the Amsler Grid test, which is a simple grid with a dot in the centre. Normal people will see straight, vertical and horizontal lines, whereas people with AMD will see wavy lines.
The diagnosis is achieved by using an eye chart (visual acuity test), examining the inner layer of the eye (retina examination), and injecting a dye into your bloodstream (fluorescein angiogram) to identify any leaking blood vessels in your eye.
Treating AMD
AMD was discovered long before any treatment was found, said consultant ophthalmologist Dr Wong Jun Shyan.
Currently, there is no specific treatment for dry AMD. However, research suggests that some vegetables high in certain carotenoids such as raw spinach can prevent or slow down this process.
Only patients with wet AMD suffer from sudden central vision loss, thus the need for treatment, he added.
Before the latest ranibizumab intravitreal (inside the eye) injection was approved by the FDA in June last year, wet AMD was treated using thermal lasers and photodynamic therapy (PDT).
Thermal lasers burn the blood vessels behind the retina while PDT uses high-energy light beams to activate a drug injected into the body, destroying the blood vessels.
Patients undergoing PDT need to shield themselves from sunlight and strong lights until the light-active drug is excreted from the body, which is an average of 48 to 72 hours. Patients may experience recurrence with PDT, Dr Wong explained. Ranibizumab has been proven in two clinical trials to be effective in slowing down degeneration in AMD and improving vision.
However, a patient needs a loading dose (the amount of injections needed to achieve therapeutic effect) of three injections, and an estimated average of eight injections in a lifetime to treat AMD, Dr Wong said. It is a painless procedure, where the drug is injected into the eye under local anaesthesia, he explained. “However, the only downside to the treatment is its high cost. Although other off-label drugs are used, they have not been rigorously tested for AMD treatment.”
Living with AMD
After experiencing sudden visual loss, it was not the end of the world for Mary Ann. On the contrary, she took steps to cope with it.
“There was some disorientation at first,” she recalled. “I was thinking about what will happen if I was going blind. I was preparing for it, practising walking without the help of vision, and even considered renovating my house to make my movements easier.”
Although already taking steps to face the worst, Mary Ann was not giving up. “I have only two eyes. I must take care of them. So I sought treatment immediately.” She went through three and a half year's of photodynamic therapy (PDT). “I had to totally wrap myself up. I could not expose my skin to sunlight and I had to wear scarves, gloves and socks.”
After ranibizumab was available, Mary Ann had been treated with three injections. “It wasn't painful. There was just a smarting sensation when the doctor injects the local anaesthetic.” “My grandchildren's only reaction to the treatment was 'grandma, your eyes are so red!'“ Mary Ann said.
One of the side effects of ranibizumab injections is a red eye, which Mary Ann said, “would last for about 48 hours before it subsides.” “However, after the treatment, my vision was back to what it was before treatment,” she said. “My life has improved tremendously.”
Now, Mary Ann can read again.
“We must not just accept vision loss in ageing, though there are things we have to accept, like not having vision as good as a twenty-year-old,” she explained.
In overcoming AMD, a positive outlook on life may make all the difference.
By Lim Wey Wen
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