WHEN the macula, the central area of vision found on the retina of the eye, loses its light-sensing cells, this can result in an inability to read, drive, see fine details or recognise faces. This is known as age-related macular degeneration (AMD) and affects those aged 60 and above.
The principle cause of AMD is exposure to blue light which is present in all kinds of lights – from fluorescent light to candle light – and predominantly found in sunlight.
Fruits such as mangoes are rich in lutein. Unlike ultraviolet (UV) light, blue light is visible. Blue light waves are what make an object appear blue and even in yellow light, you can still find blue light. You don’t need to look directly into a source of light to be affected by its glare because blue light waves are very short and scatter easily.
In the eyes, UV light and infrared light are generally absorbed by the corneas and lens. But blue light or high-energy wavelengths of light which fall in the range of 400-500 nanometers (nm) on the visible light spectrum can pass through the cornea and lens and reach the retina directly.
Melanin, which gives eyes their colour, helps to trap high-energy light rays so that they don’t reach the macula and cause damage. This is why people with fair skin or light-coloured eyes are more susceptible to macular degeneration caused by blue light, as they have less melanin in their irises to protect the macula.
One way to cut down on the exposure to blue light is to wear sunglasses.
Dr Choong Yee Fong, Head of Cataract Service and Paediatric Ophthalmology Service in Selayang Hospital, Kuala Lumpur, says: “Everybody should wear sunglasses, even babies.”
But not all types of sunglasses protect the eyes from blue light. Golfers wear yellow-tinted sunglasses as the colour blue has been shown to block yellow. They are known as blue blockers and come in a variety of tints, including light yellow, dark yellow, amber and plum.
As we age, the lenses in our eyes naturally turn yellow, helping to filter out blue light and protect the retina from damage. But children don’t have the same protection as their lenses are clear and allow blue light to reach the retina.
As the eyes do not stop forming until the age of 18 to 20, any damage to the eyes can affect the quality of vision.
“Children’s eyes are particularly vulnerable to exposure and subsequent damage from blue light as they are born with relatively clear lenses. The amount of blue light reaching the retina at the back of the eye is greater in infants and young children than in adults,” says Dr Choong.
Studies have show that 60% to 70% of blue light reaches the back of the eye in children between the ages of two and 10, compared to only 20% in adults between the ages of 60 and 90. Hence, there is a need to protect children from the damaging effects of blue light as it affects their eyes the most during their early years of childhood.
Looking into lutein
Lutein, (pronounced “loo-teen”) from the Latin lutea meaning “yellow,” is one of 600 naturally-occurring carotenoids (a natural colorant or pigment) found in dark green, leafy vegetables and fruits that are yellow, red or orange in colour.
“It protects the retina and reduces the chances of macular degeneration, therefore providing the eyes with a window of protection,” says Dr Choong.
The benefits of lutein are different from that of vitamin A (beta-carotene) as the former protects the macula by absorbing and filtering blue light, while the latter is responsible for a person’s ability to see.
Lutein is concentrated in the outer plexiform layer of the retina, the layer before the light hits the photoreceptors.
The best source of lutein is mother’s breast milk.
Prof Dr Eric Louis Lien, of the Department of Food Sciences and Human Nutrition, University of Illinois, Urbana, says: “I would advise mothers to feed their babies exclusively with breast milk for the first six months. That will give them the protection they need. Of course, the mother also needs to eat more fruits and vegetables, which is another source of lutein, to increase the level of lutein in her breast milk.”
Lutein cannot be manufactured by the body and must be obtained from foods that are rich in lutein such as kale, spinach, bok choy, mangoes, tomatoes and carrots. As most children are averse to eating their greens, parents have to find creative ways to disguise vegetables in their children’s meals.
Although lutein has an accumulative effect in the retina, the eye’s built-in defence mechanism can weaken with age, neglect, injury and disease. A fresh supply of lutein daily will help top up your lutein “bank account” and ensure your retina is constantly shielded from the damaging effects of blue light.
