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A question we frequently hear is – how do blue light filters work? As you are reading this article on either your smartphone, tablet, or computer, you are currently being exposed to blue light which is emitted from all digital devices. If you have read some of our other articles, you will already be aware that blue light can cause significant long and short-term damage to your health.

In the short term, Blue light exposure can cause eyestrain, headaches, fatigue and sleep problems which will inevitably impact your daily productivity and mood. However, blue light exposure can also lead to more serious long-term health issues by increasing the risk of depression, heart disease, obesity, and macular degeneration, which leads to vision impairment.

Health Risks From Blue Light

These health risks have led us to develop anti blue light filters for digital devices which block blue light and reduce the risk of these health issues. So, now we are aware of the dangers of blue light, the question is – how do blue light filters work?

Firstly, it is important to note that there are different types of blue light filters. There are a variety of blue light filtering products on the market, and many phones will give you the option to shift to night mode.

Image of child sleeping clutching a teddy bear

Many smartphones’ anti-blue light settings are named ‘night mode’ due to the added importance of protecting yourself from blue light in the evening. This is because the disruption of your sleep is one of the most detrimental effects of blue light exposure.

Blue light tricks your body clock (or ‘circadian rhythm’) into believing that it is still daytime. Therefore, our body does not produce the sleep hormone of melatonin, which makes it much harder to fall and stay asleep. Inevitably, this leaves individuals feeling grouchy, tired, and unproductive the following day.

You can read more about blue light’s impact on your sleep in this article.

The Science Behind Blue Light Filters

So, how to blue light filters work?

Ocushield is a screen protector which includes a medically rated blue light filter, and can be attached to your smartphone, tablet or computer. This blocks blue light emissions while retaining the same crystal-clear screen quality and color at all times.

Contrastingly, ‘night mode’ filters must often be manually switched on by users (which people often forget to do) and result in an orange tinge which impacts how consumers view images. Not great when you want enjoy a bit of Instagram or Netflix in the evening!

Image of male hand working at laptop in the dark which puts you at risk of blue light as he has no screen protectorThe orange tinge which is emitted from devices in night mode comes as a direct result of the way screens emit light in the first place – and is completely different to the way physical filters, like Ocushield, work. As displayed in the image below, light is made up of electromagnetic particles that travel in waves (which are represented here as different colours). Together these make up the electromagnetic spectrum.

Each wave is a different length and the shorter the length, the greater the energy. Within the visible light area of the spectrum, blue light has the shortest wavelength. This means that it produces a very high amount of energy, which is the reason it can be so harmful to your eyes and health. The reason that night mode causes your phone screen to turn to that annoying orange shade is that the blue light spectrum has been actively removed from your display.

However, physical filters like Ocushield do not make your screen appear orange as they instead absorb the blue light which leaves your phone, rather than removing it from the screen’s output entirely. The result is a blue light-free screen, with none of the discolouration.

How do blue light filters workAlthough we have discussed the impact of blue light emitted from digital devices, it is important to recognize that blue light is all around us. Sources other than digital devices include the sun and LED lighting, meaning that from the minute you wake up to the second you turn off your bedside lamp before sleeping, you are exposed. Not all blue light is harmful as blue light from natural sources can be extremely beneficial for your health. The benefits from natural light include; boosting moods, improving reaction times, and increasing alertness. So, if we do not need to protect ourselves from blue light found outdoors, how can we protect ourselves from blue light found from indoor lighting?

We recommend investing in anti blue light bulbs for you house fittings to ensure your eyes are protected while at home, particularly if you have children. For activities like reading you can find bedside lamps which emit a warm, relaxing light which is perfect for allowing you to see clearly without impacting your sleep afterwards.

Tips and Tricks to Limit the Impact of Blue Light

Over-exposure to blue light can be detrimental to our health, which is why everyone should be taking precautions such as using blue light filters, particularly in this digital era where everyone is glued to their phone. We highly recommend purchasing a blue light filter to protect yourself from any health risks and to improve your sleep. However, here are a few tips and tricks help you get the best sleep possible:

1. Switch off digital devices two hours before you sleep

2. Reduce daily caffeine intake and do not drink caffeine after 4pm

3. Try your best to go to sleep and wake up at the same time each day (even weekends!)

4. Exercise for at least 10 minutes per day (yes, just 10 minutes can improve your sleep!)

5. Don’t eat sugary bedtime snacks (we recommend a banana or yogurt)

6. Try meditation in the evening to calm your body

7. Dim the lights around your house two hours before sleeping

8. Ensure you only use your bed for sleeping (a lot of people are guilty of working from home in bed!)

9. Ensure your room is a tranquil place to be (yes, that does mean decluttering!)

10. Write worries down in a notebook before going to sleep (to prevent worrying about them all night)

We hope that we have answered your questions on how blue light filters work and have given you some helpful tips to improve your sleep. Please comment any further queries or future article requests below!




I'm Dhruvin - the creator of Ocushield. I'm also a qualified optometrist and with the help of a team of clinicians, I have researched and developed Ocushield products whilst at City university, London. Ocushield products have served over 50,000 customers. That’s over 100,000 healthier, happier, better-sleeping eyes.