Blue light is part of visible light, close to UV (Ultraviolet light) in the light spectrum, made up of the blue to violet range of colours.
Naturally produced by the sun throughout the entire year, blue light is normal and healthy in moderate quantities. It is the light rays at the blue end of the visible light spectrum that make the sky look blue on a clear day!
In artificial environments, however, blue light is emitted by fluorescent light bulbs as well as LEDs (light emitting diodes) in the displays of smart phones, tablets and laptops.
Blue light – good or bad?
Blue light is important to our visual processes including colour perception, and, most importantly, it triggers the pupillary reflex to safely regulate the amount of light entering the eye through the pupils.
It is also vital to our body for establishing our ‘biological clock’, the circadian rhythm, that lets us know when to sleep and when to wake up. The importance of this is appreciated when it is upset and we become sleep deprived or jet-lagged.
Blue light is crucial, too, for maintaining proper memory function, cognitive ability, alertness and also for general mood regulation. As such, it has been used for medical treatment of SAD (Seasonal Affective Disorder) as well as in phototherapy and treatment of skin conditions.
The blue to violet light range, however, can cause harm since it is the most intense light visible to the human eye. Light at these wavelengths can constitute a real danger, triggering eye damage that eventually causes disease. This “blue light hazard”, as it is sometimes referred to, is sparking growing concern due to the potential danger that it can cause to critical structures within the eye.
What this means for our eyes
The cornea and lens of the adult human eye are naturally very effective at preventing most of the UV radiation from the sun from reaching the retina which is the sensitive inner lining at the back of the eye.
Almost all visible blue light, however, is able to pass through, penetrating deep into the eye and reaching the retina, potentially harming the important retinal cells and causing long term damage.
Because of its high energy level, this blue light can induce and accelerate photochemical reactions on the outer surface of the retina. This can potentially damage the photoreceptors and cells in the pigmented layer that nourishes our vital retinal visual cells, i.e. the retinal pigment epithelial (RPE) cells.
When this retinal cell degeneration accumulates over a lifetime, the cells begin to cluster together and this has been found to cause AMD (Age-related Macular Degeneration). This cell clustering affects the central part of vision, making it difficult to recognise faces, to read or to watch television and can, in some cases, lead to permanent loss of sight.
It is difficult to know how much exposure to blue light is safe before retinal damage is initiated, but eyecare specialists are growing increasingly concerned about the added effect of man-made blue light coming from digital device screens.
This is one reason why it is extremely important to schedule a regular, comprehensive eye exam to monitor eye health and detect any retinal issue in its early stages.
Protect your eyes from blue light damage
The fact that blue light is both good and bad for the eye means that we need to protect the eye from the harmful aspects of blue light without denying it the blue light necessary to maintain our important physiological functions.
At Insight Optometrists, all of our lenses come with “blue control” as a standard feature, meaning that they selectively filter out harmful wavelengths, transmitting only the beneficial ones. This is achieved without heavy tinting, allowing essential light to pass into the eye in order to preserve vision and well-being.
Our special lenses reduce exposure to blue light, both coming directly in to the front of the lens and reflecting off the back surface, whilst maintaining excellent colour transmission and transparency. The eye’s necessary visual and non-visual functions are maintained whilst exposure to hazardous wavelengths is reduced.
In vitro testing has confirmed that these lenses significantly reduce the death of retinal cells and hence are effective in the prevention of AMD by minimising direct blue light exposure to the eyes.
A further benefit of blue light filtering is that visual contrast is improved, allowing the eyes to do less work whilst maintaining good vision, vastly improving eye comfort. The lenses also reduce glare and are anti-reflective, making them perfect for viewing a computer screen and other digital devices.
Special precautions against blue light
Children’s eyes, and those of people recovering from cataract surgery, are more vulnerable and need extra protection from the negative effects of blue light.
Since their eyes are still developing, young children’s pupils are larger and their crystalline lenses more transparent, which means that they admit more blue light but are less efficient at filtering it. Our modern lifestyle can mean that they spend more time using digital devices, increasing their overall blue light exposure and so additional protection may be recommended when selecting their glasses.
Cataracts are caused by a build-up of protein on the lens of the eye, making it cloudy. This natural ageing effect blocks some of the shorter wavelength blue light and, after cataract surgery, care must be taken since the new, replacement lens may be less efficient at protecting the retina. Blue light filtering lenses may be very beneficial in this situation, especially for exposure to intense sunshine or long hours of digital screen use.
At Insight Optometrists, we strive to provide the most complete protection in terms of your visual health.
Contact us now for a full eye health check and to find out which lenses best suit your needs when protecting your eyes from the dangers of blue light.