UNDERSTANDING BLUE LIGHT
Stepping outdoors into sunlight; flipping on a wall switch indoors; turning on your computer, phone or other digital device — all of these things result in your eyes being exposed to a variety of visible (and sometimes invisible) light rays that can have a range of effects.
Most people are aware that sunlight contains visible light rays and also invisible ultraviolet rays that can tan or burn the skin. But what many don't know is that the visible light emitted by the sun comprises a range of different-colored light rays that contain different amounts of energy.
What Is Blue Light?
Sunlight contains red, orange, yellow, green and blue light rays and many shades of each of these colors, depending on the energy and wavelength of the individual rays (also called electromagnetic radiation). Combined, this spectrum of colored light rays creates what we call "white light" or sunlight.
The Light Spectrum
Without getting into complicated physics, there is an inverse relationship between the wavelength of light rays and the amount of energy they contain. Light rays that have relatively long wavelengths contain less energy, and those with short wavelengths have more energy.
Rays on the red end of the visible light spectrum have longer wavelengths and, therefore, less energy. Rays on the blue end of the spectrum have shorter wavelengths and more energy.
The electromagnetic rays just beyond the red end of the visible light spectrum are called infrared — they are warming, but invisible. (The "warming lamps" you see keeping food warm at your local eatery emit infrared radiation. But these lamps also emit visible red light so people know they are on! The same is true for other types of heat lamps.)
On the other end of the visible light spectrum, blue light rays with the shortest wavelengths (and highest energy) are sometimes called blue-violet or violet light. This is why the invisible electromagnetic rays just beyond the visible light spectrum are called ultraviolet (UV) radiation.
The Perils and Benefits Of UV
UV rays have higher energy than visible light rays, which makes them capable of producing changes in the skin that create a suntan. In fact, the bulbs in tanning booths emit a controlled amount of UV radiation specifically for this reason.
But too much exposure to UV causes a painful sunburn — and even worse, can lead to skin cancer. These rays also can cause sunburned eyes — a condition called photo keratitis or snow blindness.
But ultraviolet radiation, in moderation, also has beneficial effects, such as helping the body manufacture adequate amounts of vitamin D.
Blue light contributes to digital eye strain; computer glasses from Jainam lenses block blue light to increase comfort.
Generally, scientists say the visible light spectrum comprises electromagnetic radiation with wavelengths ranging from 380 nanometres (nm) on the blue end of the spectrum to about 700 nm on the red end. (By the way, a nanometre is one billionth of a meter — that's 0.000000001 meter!)
Blue light generally is defined as visible light ranging from 380 to 500 nm. Blue light sometimes is further broken down into blue-violet light (roughly 380 to 450 nm) and blue-turquoise light (roughly 450 to 500 nm).
So approximately one-third of all visible light is considered high-energy visible (HEV) or "blue" light.
Key Points About Blue Light
Like ultraviolet radiation, visible blue light — the portion of the visible light spectrum with the shortest wavelengths and highest energy — has both benefits and dangers. Here are important things you should know about blue light:
Blue light is everywhere.
Sunlight is the main source of blue light, and being outdoors during daylight is where most of us get most of our exposure to it. But there are also many man-made, indoor sources of blue light, including fluorescent and LED lighting and flat-screen televisions.
Most notably, the display screens of computers, electronic notebooks, smartphones and other digital devices emit significant amounts of blue light. The amount of HEV light these devices emit is only a fraction of that emitted by the sun. But the amount of time people spends using these devices and the proximity of these screens to the user's face have many eye doctors and other health care professionals concerned about possible long-term effects of blue light on eye health.
Blue Light Can Damage the Photosensitive Cells of the Eye
Excessive exposure to blue light has been shown to damage the photosensitive cells of the eyes that include rods and cones. Blue light waves are shorter and have more energy than their longer, weaker counterparts. These High Energy (HEV) Blue light waves tend to scatter more in the eye. Studies done on mice have proved that cumulative exposure to blue light can damage the photoreceptors of the eye. It also causes accumulation of fluid in the retina as well as rupture and leaking of tiny blood vessels in the photoreceptor level of the macula.
HEV light has been proved to significantly increase the rate of cell division which is associated with the development and growth of cancer. In some animal studies, blue light has caused the development of uveal cancer in animals which had no previous evidence of cancer. In other models, an existing uveal cancer drastically increased its rate of cell proliferation in response to blue light. Blue light can damage eyes to the extent that it has the potential to cause cancer. It’s therefore a good idea to limit your exposure to it as much as possible.
Children under 9 years old are very susceptible to damage of the photoreceptor cells by blue light. This is because they possess very little protective macular pigment in their eyes that reduce the amount of light reaching the retina. Consequently, not even a little blue light is filtered out hence extensive damage may be done if their eyes experience over-exposure to blue light. You should, therefore, restrict the use of computers, phones and other handheld devices, especially in dim lighting in order to protect their eyes.
A protective pigment in the eye is melanin, which is brown. The amount of melanin pigment in the eye determines the colour of the eyes. Less melanin means that the eyes are more vulnerable to damage by blue light. For this reason, those with blue eyes are more susceptible to cataracts or macular damage since they have the least amount of melanin in their eyes. Green eyes have a larger amount of melanin and are less susceptible. Hazel and brown eyes show the least susceptibility.
Jainam Solution: Our glasses block UVA + UVB and High Energy Blue light (HEV) from your digital screens and prevent digital eye strain. This helps you get a good sleep, and prevents the long-term issues related with disrupted melatonin and sleep disorders.
HEV light rays make the sky look blue.
The short-wavelength, high-energy light rays on the blue end of the visible light spectrum scatter more easily than other visible light rays when they strike air and water molecules in the atmosphere. The higher degree of scattering of these rays is what makes a cloudless sky look blue.
The eye is not very good at blocking blue light.
Anterior structures of the adult human eye (the cornea and lens) are very effective at blocking UV rays from reaching the light-sensitive retina at the back of the eyeball. In fact, less than one percent of UV radiation from the sun reaches the retina, even if you aren't wearing sunglasses.
(Keep in mind, though, that sunglasses that block 100 percent of UV are essential to protect these and other parts of the eye from damage that could lead to cataracts, snow blindness, a pinguecula and/or pterygium, and even cancer.)
On the other hand, virtually all visible blue light passes through the cornea and lens and reaches the retina.
Jainam Solution: Our glasses block UVA + UVB and High Energy Blue light (HEV) from your digital screens and prevent digital eye strain. This helps your eyes, body, and mind stay healthy, and keeps you performing. It’s a game changer helping people save their eyes from staring at screens!
Blue light exposure may increase the risk of macular degeneration.
The fact that blue light penetrates all the way to the retina (the inner lining of the back of the eye) is important, because laboratory studies have shown that too much exposure to blue light can damage light-sensitive cells in the retina. This causes changes that resemble those of macular degeneration, which can lead to permanent vision loss.
Although more research is needed to determine how much natural and man-made blue light is "too much blue light" for the retina, many eye care providers are concerned that the added blue light exposure from computer screens, smartphones and other digital devices might increase a person's risk of macular degeneration later in life.
Jainam Solution: Our glasses block UVA + UVB and High Energy Blue light (HEV) from your digital screens and prevent digital eye strain. By blocking blue light, unnecessary stress on the eyes and mind is reduced which prevents both short-term and long-term chemical & biological process of health degradation.
Blue light contributes to digital eye strain.
Because short-wavelength, high energy blue light scatters more easily than other visible light, it is not as easily focused. When you're looking at computer screens and other digital devices that emit significant amounts of blue light, this unfocused visual "noise" reduces contrast and can contribute to digital eye strain.
Jainam Solution: Our glasses block UVA + UVB and High Energy Blue light (HEV) from your digital screens and prevent digital eye strain. Research has shown that Jainam lenses block blue light with wavelengths less than 450 nm (blue-violet light) and increase contrast significantly.
Blue light protection may be even more important after cataract surgery.
The lens in the adult human eye blocks nearly 100 percent of the sun's UV rays. As part of the normal aging process, the eye's natural lens eventually blocks some short-wavelength blue light as well — the type of blue light most likely to cause damage to the retina and lead to macular degeneration and vision loss.
If you have cataracts and are about to have cataract surgery, ask your surgeon what type of intraocular lens (IOL) will be used to replace your cloudy natural lens, and how much blue light protection the IOL provides. After cataract surgery you might benefit from eyeglasses that have lenses with a special blue light filter — especially if you spend long hours in front of a computer screen or using other digital devices.
Jainam Solution: Our glasses block 100% UVA + UVB. Thus, prevent screen-related eye issues.
Not all blue light is bad.