In France, almost 4 in 10 people suffer from this visual impairment which generally develops during childhood or adolescence.
Myopia occurs when the eyeball is too long or the cornea is too curved and causes distant objects to appear blurred.
In recent years, ophthalmologists have noted an increase in the prevalence of myopia in the United States and Europe. In France, 40% of the population is affected, compared with 20% ten years ago. Young people are affected almost twice as much as older people: myopia affects 25-30% of young people aged 16 to 24, according to the National Union of Ophthalmologists in France (SNOF). In urban areas of China, Japan and South Korea, myopia affects 80 to 90% of young people at the end of secondary school.
Myopia is partly genetic. Before the age of 12, the development of myopia is largely heredity. A child is twice as likely to develop myopia if one of his/ her parents is affected. If both parents have myopia, the risk is tripled.
The appearance of myopia in a young child is indicated by very specific behaviour: (s)he gets closer to his sheet, the TV screen or tablet, and squints at the board in class. A consultation with an ophthalmologist is therefore necessary, even if the child is only 2 or 3 years old.
Myopia is increasing in industrialised countries, and is three times more prevalent in highly urbanised areas than in rural areas.
Genetic factors alone cannot explain this increase, and environmental factors are now being called into question, such as the increase in the amount of time young people spend in front of screens (television, tablets, computers, smartphones, etc.) that requires near vision, and increased exposure to artificial light.
External, natural light can stimulate the production of a neurotransmitter, dopamine, known to regulate the growth of the eyeball. Secreted in sufficient quantity, it can thus prevent the eyeball from growing too long.
It would appear that children who played outdoors the most are be less likely to develop myopia by the age of 15 than those who spent more time indoors, regardless of physical activity. Encouraging children to spend more time outdoors (at least 3 hours a day) could thus help to limit the increase of myopia in the population.
The earlier myopia begins to develop, the more progressive and significant it will be.
Myopia is considered to be:
- Low between -1 and -3 dioptres,
- Moderate between -3 and -6 dioptres
- High over -6 dioptres
As a result of the eyeball being too long, the retina is stretched: this is the reason why high myopia weakens the eye, increasing the risks of developing certain pathologies: early cataracts, glaucoma or retinal detachment..
Another form of myopia can develop in teenagers or young adults. This is the notorious “accommodative” myopia found in students: as a result of having their noses stuck in their books or eyes glued to screens (computers, tablets, video games, etc.), they can no longer adjust their eyesight when they look into the distance.
In order for near vision not to damage distance vision, it is recommended to take breaks every 2 hours when you have to spend a lot of time staring at books or a screen.
Whatever the visual impairment,
DRL night lenses from the Precilens laboratory
are most often recognised as the most effective solution to reduce and correct myopia with or without astigmatism.