Children and excessive exposure to digital screens
The World Health Organisation (WHO) published on 24 April the New guidelines on 'Physical activity, sedentary behaviour and sleep for children under 5 years'. These guidelines recommend an increase in physical activity and hours of sleep and, in addition, dwell on the time children should spend sedentary, i.e. in front of screens watching television, videos and video games.
Computer Vision Syndrome
The time spent watching the screen, according to WHO recommendations, should be:
-Age 0-1 year: the recommended exposure time is zero.
-Age 2 years: no more than one hour per day and, indeed, less time is preferable.
-Age 3 to 4 years: no more than one hour.
According to the guidelines, the sedentary behaviour of children and young people is a risk factor for overall mortality and increased obesity.
In addition to these important consequences, prolonged exposure to screens can lead in children and adults to what is referred to as "Computer Vision Syndrome"(CVS or computer vision syndrome), the incidence of which is rising sharply, especially among children.
CVS describes a group of vision-related problems resulting from prolonged use of computers, tablets, e-readers and mobile phones. The level of severity of these alterations seems to increase with increasing time of exposure to the digital screen.
I symptoms most common associated with CVS are: eye fatigue, headaches, blurred vision, dry eye, neck and shoulder pain.
These symptoms can be caused by several screen-related factors, such as: poor lighting, glare from digital screens, improper viewing distances, inadequate seating, incorrect vision problems and, of course, a combination of all these factors.
These symptoms are felt and experienced to varying degrees by users, depending on subjective visual capabilities and the amount of time spent looking at a digital screen. Inadequately corrected vision problems such as hypermetropia and astigmatism, inadequate focusing or eye co-ordination skills, and changes related to the ageing of the eyes (presbyopia), can contribute to the onset of visual symptoms when using a computer or a device with a digital screen.
Many of the perceived visual symptoms are temporary and diminish when exposure is discontinued, however, some individuals may experience a continuous reduction in visual abilities, including blurred distance vision. If nothing is done about the cause, symptoms not only recur but may worsen.
How to intervene?
You cannot expect or think that children do not use modern technological devices, but you can intervene in their approach, in order to reduce the risks of eye and vision problems arising from the use of screen devices.
The behaviours to be put in place to limit risks include:
- frequent pauses to rest their eyes: a very useful technique when using a computer or other digital devices is the '20-20-20 rule', i.e. every 20 minutes stop looking at the screen for at least 20 seconds to look at something at least 20 metres away. This process relaxes the eye muscles and prevents fatigue;
- stretching or lengtheningDuring the short breaks associated with the 20-20-20 rule, the child/adult must get up from the desk and stretch in order to relieve muscle tension that causes discomfort in the eyes, head, neck and body in general. Stretching also helps to increase blood flow and stay alert;
- more time in the open airIt serves to relieve the tension associated with computer vision syndrome.
For those who spend a lot of time at computers for work, it may be useful to assess the general set-up of the workstation for computer use, i.e:
- position of the computer screen, many people find it more comfortable to view a computer when their eyes are facing downwards. Under optimal conditions, the computer screen should be 15 to 20 degrees below eye level, considered the centre of the screen, and 50-70 cm away;
- lighting, position the computer screen in such a way as to avoid glare, especially lighting from above or from windows; it is also advisable to use low-voltage bulbs for desk lamps;
- anti-glare screensIf glare from light sources cannot be minimised, it is advisable to use an anti-glare filter;
- sitting, chairs should be comfortably upholstered and conform to the body, the height of the chair should be adjusted so that the feet rest on the floor. If the chair has armrests, they should be adjusted to provide support for the arms while typing, while the wrists should not rest on the keyboard while typing.
In order to prevent and reduce the development of symptoms associated with Computer Vision Syndrome, it is important to combine regular eye examinations with correct lifestyle habits, both in work and leisure time.
Sources:
-Computer vision syndrome (a.k.a. digital eye strain). Mark Rosenfield. Optometry in Practice 2016 Volume 17 Issue 1 1 - 10.
English 
Italian