There is no cure for age-related macular degeneration, but vitamins and antioxidants can stop it from robbing your sight. POON CHIAN HUI reports
Madam Daisy Lim, 75, went blind in her left eye in 2007 from age-related macular degeneration (AMD).
With no cure for the disease, what she is banking on to prevent her right eye – also afflicted with AMD – from going the same route is simply a diet packed with eye-friendly nutrients.
AMD usually sets in as one ages and destroys central vision, causing symptoms like blind spots in the central field of vision.
It occurs in two forms – dry and wet.
Wet AMD occurs when abnormal blood vessels grow under the macular – a small central region of the eye's retina – and leak proteins and bleed.
The dry form occurs when retinal pigment cells that are crucial for vision break down. It is less severe and appears in about 90 per cent of AMD patients.
The World Health Organization said that AMD is the leading cause of blindness in developed countries.
Supplementing one’s diet with vitamins and antioxidants is the only proven method to delay the onset of advanced AMD, said Dr Ajeet Wagle, a consultant ophthalmologist at Khoo Teck Puat Hospital.
“Powerful antioxidants like vitamins C and E, beta-carotene and zinc can slow AMD progression as the disease is believed to be caused by oxidative damage that occur when light enters the eye,” he said.
Antioxidants interrupt free radical reactions, the cause of oxidative damage.
While not a cure-all, previous studies did suggest that a diet rich in green leafy vegetables – which contain several antioxidants – can lower one’s risk of developing AMD, said Dr Ian Yeo, a senior consultant ophthalmologist at the Singapore National Eye Centre.
However, the high dosages required are difficult to achieve from diet alone.
Hence, Madam Lim, who seeks treatment at SNEC, takes supplements tailored for patients like her on top of a healthy diet.
The prescribed tablets contain antioxidants zinc and copper, as well as vitamins A, C and E.
They are in dosages recommended by the landmark age-related eye disease study in 2001, which serves as the guideline for supplement use for AMD worldwide.
This study showed that daily consumption of supplements can cut the risk of advanced AMD by 25 per cent and lower the risk of vision loss by 19 per cent.
It recommends a daily intake of 500mg of vitamin C, 400 units of vitamin E, 80mg of zinc, 15mg of beta-carotene and 2mg of copper.
These standards are for non-smokers with moderate severity of dry AMD in one or both eyes, and for those with advanced AMD in one eye.
Smokers have to adhere to a different combination of vitamins.
Dr Yeo said: “They will need to avoid beta-carotene as high doses of this nutrient have been linked to increased rates of lung cancer.”
AMD sufferers should also take care not to overdose on supplements.
It is best that they take supplements on the advice of an eye specialist, as the required dosages are higher than the recommended daily intake for healthy people, said Dr Wagle.
“Patients should also be aware of the contents of the tablets prescribed by their eye specialist so that they avoid additional doses of the same vitamins in their daily regimen,” he added.