View, myopia and glasses: the real and the false to know

“THE‘Human being is the eye with which the universe has learned to observe itself, “said the physicist Victor Weisskopf. We inherited our eyes by organisms which, about 540 million years ago, during the Cambrian period, developed groups of cells sensitive to light. It is one of the most fascinating stories of adaptation to life, because they are the first eye stains that have imprinted the evolutionary jump that changed the fate of the living, up to us. Our eyes are said to be a window on the world, but they are also a window on time. They understand the light and the dark and thus synchronize our biological clock with the rhythms of the planet. Many things are said. That bringing the worst glasses visual defects, that we should eat carrots and that the computer causes myopia. Precisely because so important, mysterious in their biological complexity and enclosed in symbolisms and metaphors, the eyes are subject to convictions that are not always exact. Here are to demolish and which to keep.

Myopia is a direct effect of the hours spent in front of the computer and TV

FALSE: As far as we know, one could remain a nice piece in front of the television without being more subject to myopia of others who do not do it (if it compensated with outdoor life). On the other hand, if the screens directly caused the deformation of the eyeball, the large manufacturers would be submerged by the claims for compensation for damages.

Watch cell phones and pc tired the view

REAL: Our eyes are not made to focus on objects close to the face for long periods of time. Those of our ancestors had to be trained to intercept a prey to be able to hunt it or a fruit between the branches to collect it. The way in which our crystalline works is precisely a legacy of life in the Pleistocene. The lens inside the eyeball modifies its shape to automatically adjust the focus through accommodation, that is, a series of micro -novaments regulated by a ring of muscle fibers arranged all around, in the ciliary body. When the eye focuses something in the distance, the crystalline flattens itself, while it becomes more convex if the object is close. When we oblige our internal lens to maintain the same curvature for hours, because we only see electronic devices such as mobile phones, computers and home walls, it is as if we kept a biceps perpetually contracted. The eyes, like us, get tired.

Stay too much in front of the screens of electronic devices drys the eye

True: the problem, when you are for hours in front of smartphones, computers and TVs, is that the wink, the rapid and momentary closure of the eyelids is reduced, and therefore the tear film evaporates, with symptoms ranging from itching to redness (up to the dry eye syndrome in predisposed patients).

After 20 minutes on the computer you should look out the window

REAL: An easy advice to relax the ciliary muscle that contrasts the crystalline is to keep in mind the 20th rule: after 20 minutes at the computer, looking out the window, watch over 20 meters away for at least 20 seconds.

Taking a break from glasses can prevent visual defects worsening

FALSE: Some believe that the eye gets used to the lenses and that for this the visual defects can worsen. It’s not true: who needs glasses should wear them.

Spending more time in the open air helps the view

REAL: searches (conducted above all on children) suggest that being outdoors can reduce the risk of developing myopia. The reason is not entirely clear, but it seems that sunlight stimulates the release at the level of the retamine retina, a chemical mediator who participates in the refractive function of the crystalline.

There are no lenses to block myopia in children

FALSE: There are new lenses called defocus, that is, defocalized, suitable for children with myopia. They allow to obtain a clear image on the central part of the retina and a view defocalized in the peripheral area of ​​the retina. This reduces the stimulus to the growth of the eyeball, slowing down the speed of progression of myopia. There are different types (not reimbursable by the National Health Service).

Five billion people will be myopians

REAL: Myopia is the visual defect that has undergone the most decisive increase in recent decades. Scientists fear that in 2050 it could concern almost five billion people. There are hereditary causes (it seems that 25 genes related to the development of the disorder), but the environmental factors would play an important role, including the spending a lot of time indoors and little outdoors. Among the most affected countries there is China, where over 80 percent of high school students bring glasses.

It is useful to set the dark mode in smartphones

REAL: the light to us may seem neutral, because the brain corrects and compensates for information, but is made up of seven colors: red, orange, yellow, green, blue, indigo (an intense blue), violet. Depending on the moments of the day and artificial sources, one of the shades predominates on the others. For our biorhythms, the blue light of electronic devices, computers, tablets, cell phones and televisions is a disaster, because it is the same dominant light gradation in the daytime sunlight. The wavelengths corresponding to blue inhibit the production of melatonin, the molecule that promotes sleep, and give the biological clock a sign of alarm clock. By majority of smartphones, the dark mode, more yellowish, can now eliminate blue light.

Reading in the dark can cause myopia

FALSE: The darkness does not directly affect myopia, but if the lighting is so scarce that it has to keep the book or the tablet near the face, the risks of eye fatigue increases, which can generate temporary symptoms such as eye dryness, headache and difficulty concentration. Hypermetropic should not read in an environment with little light.

Sunglasses are not so useful

FALSE: There is a reason why experts recommend not to fix the sun. Too much exposure to ultraviolet rays A and B of sunlight can cause irreversible damage to the retina and can also increase the risk of developing cataracts. Wearing sunglasses offers sun protection. It also applies to children and adults who have been operated on cataracts.

Carrots protect against macular degeneration

REAL: Some research suggests that substances from the antioxidant properties of carrots are good for eye health. A large US clinical study (promoted by the National Eye Institute and conducted with the administration of supplements) has discovered that beta -carotene and vitamins C and could slow down the progression of the macular degeneration linked to age.

Eliana Liotta is a journalist, writer and scientific popularizer. On Iodonna.it and on the main platforms (Spreaker, Spotify, Apple Podcast and Google Podcast) you will find its podcast series The good I want to.

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