We go back to school and our eyes are at the forefront of the organs of our body protagonists for the daily effort required. The ABC of the prevention of vision disorders requires the knowledge of some rules of behavior also because the visual application continued for long periods typical of recent times, negatively affects both the visually impaired and the visually impaired child. Too many hours on the computer or smartphone are bad for your eyesight? What is the daily ‘right dose’ of hours of visual application? How many breaks are needed in the eyes of a child who studies? These are some of the doubts that parents struggling with the start of the new school year may have to which Andrea Piantanida, eye surgeon of the Lariano Eye Center, Cernobbio-Como, and member of the Scientific Committee of the Salmoiraghi & Viganò Foundation responds.
Eyes under stress
If first we blame our children for the excessive use of electronic devices in their free time, with the spread of Distance Learning we have had to give in to the need to use them more frequently, even for school purposes. With what consequences? “The greater use of near vision than in the past – replies Piantanida – has led to a considerable increase in both the incidence of refractive defects and focusing disturbances. The indiscriminate use of mobile phones, tablets and computers even in free time is bringing out a series of problems that until recently were clinically irrelevant. Currently myopia – says the expert – is a real health emergency with statistical analyzes that report a prevalence of this refractive defect in adolescence equal to about 70-80% in the Asian race and about 40% in the Caucasian race. “.
Symptoms of accommodation stress
The use for too many hours of computers or other electronic devices that are used at a distance of 20/40 centimeters, involves a continuous stress of the accommodation and a failure to relax the focusing muscles with a possible blockage of the accommodation itself. How to understand that there is this criticality? “The parent – explains the ophthalmologist – must try to observe if there is also a reduction in the speed with which the pupils react to a light stimulus”. Other signs are the reading attitude of the child who tends to keep the book very close together, and reports that he does not see the blackboard well and that he has severe headaches while reading.
Pseudomiopia
The consequence of this is the onset of a fictitious myopia or pseudomyopia caused by what is called ‘accommodative spasm’, that is in practice a prolonged close activity, such as reading a book or a video game on the smartphone, can lead to a spasm of the ciliary muscle (which has the task of regulating accommodation), and inducing a fictitious increase in diopters. It is as if the eye were no longer able to focus objects at different distances, but remained in conditions of total accommodation. “Only the correct refraction analysis performed by the ophthalmologist, with the use of specific eye drops – explains Piantanida – allows you to avoid the prescription of a non-existent refractive defect, with all the consequences that such a prescription would entail”.
Less hours on computers and smartphones, more time outdoors
However, when myopia is actually present, it is good to understand what are the behaviors that can prevent it from worsening. Recent epidemiological studies have shown that not only near visual engagement increases myopic progression, but conversely that outdoor activity reduces the risk of myopia with a percentage of advantage equal to 2% for every hour spent at the open per week.
The blue light of the screens
Can the characteristic blue light emitted by the screens of mobile phones, tablets and computers be harmful to the eyes? “To date – replies Piantanida – no scientific work has shown clinically significant damage to the eye at an organic level due to exposure to blue light. The quantity of blue light, in fact, is such that it does not induce oxidative damage as it happens experimentally for larger quantities ”.
Digital insomnia
Rather, the real problem is the so-called ‘digital insomnia’. Exposure to blue light actually causes an alteration of the sleep-wake rhythm by influencing the secretion of melatonin (the sleep hormone that physiologically increases in the evening), as it reduces its production. The consequence is an alteration in school performance the next day. What to do then? “We must activate the blue light filter on the screens”, replies the ophthalmologist, and it is important to prevent children and adolescents from using electronic devices at least two hours before bedtime “.
The interactive whiteboard at school
Some parents are concerned that the use of the IWB, the interactive multimedia whiteboard, can damage the eyes. “In reality – explains Piantanida – it is only a large computerized screen for which the same recommendations that are generally made for the use of computers apply: it is useful to enhance the contrast using the IWB in dim light, thus reducing the phenomenon of glare and it is advisable to position yourself in front, avoiding the lateral positions that make focusing difficult “.
The sight-saving rules
But concretely, what is the right ‘dose’ of hours allowed for children on electronic devices? “Parents – replies Piantanida – have the task of enforcing some simple rules for their children: to take breaks of at least 5 minutes for every hour of use of the video terminals or 15 minutes for every 2 hours of use; during breaks avoid a visual commitment to near but engage in activities that do not involve accommodation and spend more time outdoors to take advantage of the beneficial effects of UV rays on the control of myopic progression. Not only that: “Parents should get into the habit of shooting the child who uses incorrect postures to facilitate the good balance of accommodation and visual convergence”, suggests Piantanida.
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