During my final year of medical school, I remember seeing my friend Aleks read on his laptop and it had a dim yellow light. He briefly explained that he read somewhere that light emitted from our screens was not very good for our eyes. I downloaded an app he recommended and never revisited the topic again. Too focused on my exams, I did not bother to give it any more thought. Fast forward few months to a year later, iphone has an update and one of the features is called “Night shift“.  My husband was on his phone and says “I wonder what this night shift does”. The very second that the colour of his screen changed to an amber tone, I remembered that I had seen that before. Not on my phone, but on my laptop.


Night shift is a feature available on your apple products. Your iPhone, iPad, Ipod touch, Macbooks and hopefully whatever else is out there. It automatically adjusts the colour of your screen from the usual LED blue light to a warmer tone which is easier on your eyes.

Why should you use the night shift on your iPhone and other devices?

I will introduce you really quickly to a hormone called Melatonin. Melatonin is a very important hormone produced by the pineal gland in our brains. One of the main functions of this hormone is its role in regulating other hormones in our body and helping to maintain our circadian rhythm. Our circadian rhythm is an internal 24-hour clock that plays a major part in determining when we fall asleep and when we wake up. Our level of melatonin increases when it is dark and when it is bright, our body produces less melatonin; therefore making us more awake.

Before the days of LED lights and other artificial lighting, we relied mostly on the sun which helped to regulate our circadian rhythm. These days, the world is more illuminated at night therefore messing with our 24hour clock and our melatonin levels. This may lead to sleep disorders. Studies have also shown that this has a correlation with depression, obesity, heart disease and some cancers.  People who sleep less have a decrease in Leptin – a hormone that decreases your appetite and makes you feel full. And these people tend to eat more, exercise less and become more depressed. In the long run, this only gets worse; leading to low self-esteem and coping.

How does this happen?

Not all light has the same effect. The one in particular to be most aware of is “Blue light” or “short wavelength” (around 460 to 480 nm). This is the most melatonin suppressive light. And this is the same light in LED lamps which are present in most of our devices. Our mobile phones, tablets, computer screens and even our TV screens. LED light is energy efficient and therefore the preferred choice. However it contains a lot of blue light. Blue light is useful in the daytime because it boosts our memory and focus and further improves our mood. At night, the effect of this light is terrible. Besides messing up our sleep, there have been studies showing the effect of blue light on the physiology of our eyes and the damage it causes.

A Harvard sleep researcher Stephen Lockley said, ” Light at night is part of the reason so many people do not get enough sleep”. The average person takes their phones to bed. We very often spend hours each night staring into our phone screens without realizing the harm this is causing to our health.  It is important to know that it is not enough to just dim your screen. Research performed at The University of Toronto showed that your melatonin was decreased just as badly when your screen is dimmed because your retina is very sensitive to blue light and can still detect it. Recently I read an article about a man who met with Steve Jobs. He asked “So, your kids must love the iPad?” And Steve Jobs replied saying “They haven’t used it; We limit how much technology our kids use at home.” Even the founder was low-tech with his children so why should we not as well.


NIGHT LIGHT on Windows 10: This works in the same way as Night shift. You are able to pick the time in which you would like the blue light to go off and for a warmer tone to come on. You are also able to choose how low on the yellow spectrum you would like to go.

NIGHT MODE, READING MODE, BLUE LIGHT FILTER: On Android phones like Huawei and Samsung, this mode may be called something else. You would have to check in your display settings to activate this mode. The idea is generally the same.

F.LUX: was the app I used on my laptop in medical school. As the website describes it “f.lux makes your computer screen look like the room you’re in, all the time. When the sun sets, it makes your computer look like your indoor lights. In the morning, it makes things look like sunlight again”. A very user-friendly app that you will enjoy using.

TWILIGHT: is similar to F.lux but works on your mobile phone. It makes your device screen adapt to the time of the day by filtering the blue light emitted by your phone or tablet after sunset. It uses a red filter that is way more soft on your eyes.

E-READERS: If you have to use an e-reader, be mindful of the lighting. Although companies market those with nice fancy blue light as better, remember the side-effect of this light at night time.

CANDLES: Candles produce amber -orangey light. Orange and red light are the least melanocyte suppressive light so get into the habit of using candles in the evenings.

TIME MANAGEMENT: Get more work done during the day so you do not have to be seated during the night behind a laptop screen.

HOME LIGHTING: Be mindful of the lighting in your home. Warm light is more yellow and is easier on the eyes. Also, sleep with the lights off.

BLUE LIGHT BLOCKING GLASSES: These are special glasses that block out the blue light from your screen.

GIVE YOURSELF A BREAK: Avoid screens in the last hours before bed.


Blue light: High energy, visible light used in our devices


  • Renisenb McGehee

    Hi there!! Thank you so much for publishing another great article on your blog!! This is an important topic that is not often discussed! Thank you for sharing! Have an amazing day!! 🙂

    • Cheryl John

      Hiyee ReniseNB, thanks so so much for your continued support. Have a very lovely day as well. 🙂

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