"Although our lives now depend on our computers, our bodies haven't completely come to terms with the idea.

More and more users of digital screens are complaining of visual problems, eye fatigue, dry eyes and migraines. Some are prescribed glasses and blame their digital screens, while others are convinced that their screens have aggravated their myopia. In the high-tech world, many employees worry about radiation from their screens. Their greatest fear is that their vision will be irreversibly damaged.

The good news is that numerous studies conducted in the USA as part of vision research have proved conclusively that using computers does not cause eye pathology. According to another study focusing on high-tech employees, there is no link between intensive computer work and myopia. That said, there's no doubt that screen use can lead to temporary visual problems, most of which can be easily avoided by making simple changes to our work habits.

It's worth noting that the sooner symptoms appear - within the first half-hour of screen work, for example - the more likely they are to be linked to a pre-existing visual problem. On the other hand, it's perfectly normal for our eyes to feel tired after eight hours of intensive screen work. After all, wouldn't you expect to feel sore after running a marathon?" - Dr. Andrew Fink.

This article was written by Dr Andrew Fink MD, Surgeon and Fellow of the Royal College of Ophthalmologists in the UK. We are very grateful for his contribution.

1. Visual fatigue: causes and symptoms

Excessive strain on eye muscles

Visual (or eye) fatigue is the result of intensive work on the eye muscles, or in other words, when you put too much strain on your eyes. This means that eyestrain can occur as a result of any activity that places intensive demands on the eyes, such as reading a printed score in a small format, composing in an overly dark environment, or taking a long car journey.

A temporary problem

No scientific study has proven that eyestrain can lead to permanent eye disease. Common symptoms of visual fatigue are blurred vision, a feeling of heaviness, fatigue or irritation in the eye area, and migraines.

However, these symptoms are temporary discomforts, in the same way that a trip to the gym usually results in slight aches and pains. These temporary aches and pains are uncomfortable, of course, but entirely benign.

To prevent eyestrain, all you need to do is adopt a few good work habits that we share in this article.

Individual factors

• Pupil size adjustment

Pupil size changes according to lighting conditions. If ambient lighting is constantly changing, the pupillary muscles will be put under a great deal of strain, and will therefore tire more quickly.

• Accommodation

If different optic foci are far apart, the eye muscles will be called upon to move from one to the other.

• Dry eyes

The blinking frequency of our eyes is reduced when we use digital screens, resulting in dry eyes.

• Wearing ill-fitting glasses

Wearing inappropriate eyewear is tiring for the eyes, especially when working long hours in front of a screen.

• Poor viewing angle

Our eyes are designed to look straight ahead and slightly downwards, especially when reading or doing precision work. Looking straight ahead without tilting, upwards, or sideways contributes more to eye stress.

Blue light

The impact of blue light is hotly debated and has not been conclusively researched. Although it is emitted by virtually all light sources, from the sun to artificial light sources such as fluorescent and LED lighting, it is said to have both beneficial and potentially harmful effects. Light is made up of electronic particles.

Blue light has a particularly short wavelength, so the energy reaching the retina is stronger. This can lead to discomfort when the eye is exposed to it for prolonged periods. Studies have also shown a link between high exposure to blue light and retinal diseases. However, researchers have not yet determined what constitutes "strong" exposure.

It's also important to remember that computers produce far less blue light than natural light. On the other hand, other studies have shown that blue light increases alertness and the activity of brain functions, and improves our mood by promoting the secretion of endorphins.

For those concerned about the potentially harmful effects of blue light, there are a number of screen filters and 'anti' blue light glasses available.

2. Electronic ink or LCD screen?

Let's start by exploring in detail the technical characteristics of the two types of screen on the market: E-Ink and Liquid Crystal Display (LCD). E-Ink is an electronic paper display technology used in e-readers such as the Kindle. LCD technology is used in iPads, tablets, smartphones, televisions and computers.

Reading on an E-Ink screen is as close as you can get to reading a printed book, while LCD screens bring a new digital dimension. It would therefore be quite natural to conclude that E-Ink screens are better for our eyes. However, against all odds, Dr. Fink and the Association of American Optometrists claim that "the type of screen used (LCD or E-Ink) doesn't really matter". So why aren't E-Ink screens naturally better for the eyes?

Retrofitting is good for the eyes

E-Ink screen advocates often argue that the backlighting of LCD screens is harmful to the eyes. Yet this is not the case. According to the Association of American Optometrists, "backlighting makes no difference because our eyes naturally adjust to the level of brightness to which they are exposed".

What's more, thanks to backlighting, LCD screens allow you to manually adjust screen brightness, although most LCD screens do this automatically by adapting brightness to ambient light.

Carl Taussig, Director of the Digital Surface Research Laboratory at Hewlett-Packard, raises another argument. According to him, "new-generation LCD screens do not affect the eyes, since these screens update every eight milliseconds, whereas the human eye moves at a speed of 10 to 30 milliseconds".

To make digital reading more comfortable, Apple has developed Night Shift and True Tone technologies. Night Shift automatically adjusts color balance to calibrate screen brightness. True Tone automatically adjusts white balance according to ambient light, bringing it closer to paper.

To sum up, the advantage of LCD screens is that they adapt to ambient light, and so protect the eyes, which no longer have to constantly adjust to bright or dim light, providing real eye comfort.

Screen reflections are not harmful

Screen reflections are also considered to be one of the causes of visual fatigue.

Glare and reflections from the screen can reduce visibility, as the different degrees of brightness diffused on the screen force the eyes to constantly adjust the size of the pupil. However, these completely natural adjustments not only do no harm to our eyes, but can also be avoided.

Indeed, according to Dr. Fink, "reflections can easily be eliminated by adjusting the screen angle or downloading an anti-glare filter".

Finally, LCD screen manufacturers are investing considerable sums in the development of anti-glare technologies. Apple, for example, has declared that "the iPad Pro has the least reflection-sensitive screen compared to other tablets on the market".

High-definition screens offer a real advantage

Screen definition and display parameters should also be taken into account when reading on screen. In fact, when the definition is high, visibility is much clearer and the eyes are less strained. Reading, annotating and editing a score from a high-definition LCD screen offers a much richer experience, since users will be able to zoom in and view every last detail of the score without pixel effect.

The screen of the second-generation 12.9-inch iPad Pro has one of the highest definitions available on the market, at 2732 x 2048 pixels (264 PPP). By comparison, E-Ink displays are generally limited to a resolution of 1600 x 1200 pixels (150 PPP).

Dr. Travis Meredith, Chairman of the Department of Ophthalmology at the University of North Carolina, sums it up this way: "Sitting close to a TV or computer screen is not in itself bad for your eyes. It's the environment that counts.

"I read my digital scores from my iPad Pro for seven hours a day, and I've never felt any discomfort in my eyes. On the contrary, I appreciate the fact that the iPad lets me adjust the brightness or zoom in. It would simply be impossible for me to go back to reading paper scores." David Lefèvre, Conductor, Newzik ambassador

3. How can we make screen reading more comfortable?

Here are a few tips to prevent eyestrain and improve your eye health:

• Maintain a comfortable reading distance

The recommended distance is about 33 centimeters for A4 or A3 screens. It's important to ensure that the font is neither too small nor too large.

• Adjust the brightness of your screen to suit the ambient light

Your screen should be no more than 10 times brighter than your surroundings.

• Reduce glare and reflections

Adjust the position of your screen or use an anti-glare filter.

• Adjust your screen layout/angle

Ideally, the screen should be positioned 10 to 12 centimetres below the horizon.

• Place any other equipment you may need close to the screen

To prevent your eyes from scanning too great a distance.

• Regularly check that your glasses are properly adapted to your eyesight.

• Clean your screen

Dust and fingerprints reduce visibility.

• Blink!

Although it may seem obvious, we tend to blink less when we're concentrating hard. For dry eyes, use artificial tears.

• Take plenty of breaks

And follow the 20-20-20 method: pause for 20 seconds every 20 minutes, looking at an object about 20 feet (about 6 meters) away.

In conclusion, eyestrain is not directly caused by digital screens, but rather by a combination of lack of education about these new tools and bad habits.

To be properly prepared for intensive screen work, we simply need to take the time to re-educate ourselves and adopt new, healthier habits. If we manage to integrate this new approach, we'll be able to enjoy all the benefits of new technology while protecting our eyesight.