Here are some triggers and tips to save your retina from the havoc that blue light from the digital screen can torment them with.

Modern lifestyles are almost impossible to imagine without our gadgets and tech-toys caves? Should we even be bothered?

Introduction to blue light


Light is an interesting phenomenon – both from an angle of Physics and Art. The colours that are packed inside a spectrum make the world beautiful and functional. But some areas of this spectrum need human attention when we interpret them in our smartphone-age.

An inverse relationship exists between the wavelength of light rays and the amount of energy they contain. So rays with relatively-long wavelengths contain less energy, and vice versa.

The blue light comes in the visible light bracket ranging from 380 to 500 nm. It can also be sliced into two areas – blue-violet light (about 380 to 450 nm) and blue-turquoise light (around 450 to 500 nm). In essence, as much as one-third of all visible light falls into the High-Energy Visible (HEV) category. In short, blue light.

Also, rays in the red end of the visible light spectrum have less energy due to their longer-wavelengths. And rays in the blue end of the spectrum have more energy by the same logic – because of their shorter-wavelengths.

Our eyes do get exposed to them more often than we can count. When we step outdoors into the sunlight, when we switch on a bulb indoors, when we power on a gadget, we are staring into light rays of this spectrum.

Where is it? Sources, Types, and Effects

If we consider the range of sunlight, then we would find red, orange, yellow, green and blue light rays with innumerable shades and wavelengths.

The light rays that sunlight contains are both in the visible light and invisible ultraviolet range. The latter is harmful enough to cause a burn or a skin-tan.

In fact, sunlight is the largest source of blue light. Other areas where blue light is replete are – fluorescent light, compact fluorescent light bulbs, flat-screen televisions, other man-made sources and LED light.

Not that the degree of HEV light these devices emit is significant or scary. It is, often, only a fraction of the amount emitted by the sun. The problem is that people tend to spend too much time and proximity to these screens and that is making eye doctors and health care experts more concerned about the use of these devices. Eye health has become the new question that these devices are raising.

How blue light affects eyes

We do get eye strain when we look at the sun. The same is experienced when we look at a device for too long. It usually happens due to the absence of blinking movement while we are engrossed in our screens. That is the primary reason for eye strain and dry eyes, as experts from the American Academy of Ophthalmology have opined.

To add to the woes, blue light affects our body’s circadian rhythm, the natural wake and sleep cycle.  It is supposed to wake us up during the day by stimulating us. But when we use it a lot, thanks to our devices, during the night, we stay up stimulated and unable to sleep properly.

Going into a bit of biology here may help us understand the problem better. The anterior structures of the adult human eye (the cornea and lens) are great at blocking UV rays from reaching the light-sensitive retina at the back of the eyeball. So much so that, less than one percent of UV radiation from the sun can reach the retina – and that is a natural wall, even when a person is not wearing sunglasses.

So why do people associate cataracts, snow blindness, a pinguecula and/or pterygium etc. with light exposure, poor lifestyle or habits?

Blue light emitted from digital devices and the sun can change vital molecules in the eye’s retina into cell killers (self destroying molecules/ apoptotic particles). An optical chemistry research conducted at The University of Toledo found that out recently and explained that in context of age-related macular degeneration, and causes of blindness in the United States.

Continuous exposure to blue light can make the eye’s cornea and lens unable to block or reflect UV rays, as before. The professors involved in this research also explained how their experiments went deeper into macular degeneration. It was observed that macular degeneration, results in significant vision loss (mostly at ages of 50s, 60s and above) is basically the death of photoreceptor cells in the retina. Those cells need molecules called retinal for sensing light and triggering a cascade of signalling to the brain, the study stated.

You need a constant supply of retinal molecules for good vision. Photoreceptors are useless without retinal that is produced in the eye. Now if blue light exposure can lead retinal to trigger reactions that generate poisonous/ suicidal chemical molecules in photoreceptor cells, then we do have something to worry about, don’t we?

Now if we think of UV rays, we will notice that they have higher energy than visible light rays, and thus, capable of producing changes in the skin or the sunburn we know of. Similarly, it has been apprehended that these rays can cause sunburned eyes — a condition called photokeratitis or snow blindness.

We cannot ignore the benefits of ultraviolet radiation (when taken in moderation) – like helping the body to make vitamin D.

But we should keep reminding ourselves that too much exposure is always harmful, Whether to the sun or the screen. The eye strain of the modern human being is something that even Darwin was not prepared for. We need to evolve for this danger and survive again.

Even if the blue light does not injure the eye or lead to any serious damage, it does leave them dry or irritated.


Protecting your eyes from the damaging effects of the blue light

To begin with, develop a slow but steady habit of limiting your screen time to just two to three hours before going to bed. You can use nighttime settings or blue light alerts with your device’s settings itself.

Start taking regular breaks. Apply the 20-20-20 rule: It means every 20 minutes, try to shift your eyes to look at any object which is about 20 feet away, and do this for at least 20 seconds.

Be wary about an incorrect prescription for glasses or contacts. Blurriness is a warning sign. Any time you feel eye strain, take measure and expert-advice to correct it.

Change your environments. Avoid a place that brings visual discomfort or has inappropriate light settings. Try to adjust air vents while driving so that air is not blowing directly into your face.

If you have been prescribed so, wear your glasses or contacts or wield a pair of sunglasses when stepping out. Blue light filters and protective eyewear is now available to protect the eyes from harmful Blue light.

Use of artificial tears, humidifiers; or taking a moment to adjust your computer screen, so that eye gaze is slightly downward – these can help too. But what matters, above all, is to realise that blue light is something you need to be aware of.

Blink and think.


Nagesh Vuppala
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