Myopia

What are the main causes of myopia? Why are we myopic? 

In the vast majority of cases, myopia is due to an eye that is too long. You should know that when you look at something, the image of the object is supposed to form on the retina. In a short-sighted person, the image is formed in front of the retina. As a result, the brain receives a blurred image of distant objects. In some rare cases, a deformation of the cornea (cornea that is too curved) can be the cause of myopia.

Diagram illustrating myopia, a very common visual defect characterised by an eye that is too long or too powerful, causing blurred vision at a distance.

This deformation of the eye can be due to several factors: 

• Genetics: it has been shown that genetics is one of the causes of myopia. A child whose parents are both short-sighted, for example, is six times more likely to become short-sighted. However, if heredity is involved, the exact genetic origin has not yet been determined. 
• Our environment: studies also show that a lack of exposure to natural light can disrupt the growth of the eye, and thus favour the development of myopia.
• Our lifestyle: our lifestyle, and therefore our vision, is directly involved in the appearance of this visual defect. Researchers have indeed observed an impressive increase in cases of myopia among generations Y and Z. The reason for this is that close-up vision is too demanding on a daily basis. Among other reasons, the amount of time spent in front of screens (smartphones, tablets, computers, television, etc.) has increased considerably, overtaxing our near vision and consequently favouring the appearance of myopia. This phenomenon can also be observed in students, who generally spend a lot of time working (reading, writing, etc.) in close vision. This phenomenon is called "student myopia".

Ultimately, it is the combination of all these elements that causes myopia. Moreover, it is estimated that by 2050, with the rapid and radical evolution of our lifestyles, half of the world's population will be myopic. It should be noted that in 2000, myopia only affected a quarter of the world's population. 

Evolution of myopia: how can myopia be slowed down? Can myopia be stabilised?  

Today, the onset of myopia can be prevented by increasing exposure to outside light. But it has not been clearly established that this slows down the progression of myopia. The development of myopia also depends on the age of onset. The earlier myopia appears, the faster it progresses and reaches high levels. In China, for example, the first myopias appear around the age of five, and these same myopias will stabilise at around -6.00 / -8.00 dioptres, with a pathological risk. Fortunately, this is not the case for everyone. 

Myopia and presbyopia: from the age of 40, do myopes also become presbyopic? 

Presbyopia is linked to the ageing of the crystalline lens, regardless of the visual defect. Myopic people who see well at close range can, in certain cases (depending on age and level of myopia), do without their glasses to continue to see clearly at close range... But they must quickly put them back on to see clearly at a distance. Progressive lenses are therefore the best solution to avoid these acrobatics and to see clearly at all distances after the age of 40-45, without changing or removing and then putting back on your glasses.

Driving at night: why is it more difficult for me to drive at night? 

This is known as nocturnal myopia. The lack of light, the glare from car headlights and urban lighting, not to mention the difficulty in judging distances (at night, the pupil dilates more and alters the appreciation of the depth of field) make our night vision more awkward and painful. 

Myopia in children: how can i tell if my child is short-sighted? 

As early as primary school, or even kindergarten, if a child's parents are short-sighted, it is recommended that they consult an ophthalmologist in order to identify and correct any short-sightedness without delay.

The main symptoms of myopia in a child are:

• Difficulty in reading the blackboard in class.
• Failure/discouragement in team sports.
• Excessive closeness when drawing or writing.
• Squinting of the eyelids to see better.

Whether your child is short-sighted or not, the most important thing is that he or she spends as little time as possible on the screens: this activity requires a lot of close vision and a great deal of accommodation, which can lead to myopia in the long term. This is also known as student myopia, which will progress rapidly if the short-sighted person does not take regular breaks (spending time outside to see the light of day).

Glasses for short-sighted people: how should i choose my pair of glasses? 

What glasses should I choose if I am short-sighted? The best advice for choosing a pair of glasses:

• Your myopia is slight, below 1.5 dioptres: there are no restrictions on your choice of frames: drilled, extra-wide, semi-invisible (with a nylon thread at the bottom of the frame), metal or acetate, etc. Do as you please.
• You are moderately nearsighted, up to 6 dioptres: thanks to slimmed lenses, the choice of a frame remains very open to match the style you like. A myopic lens is concave, i.e. thicker at the edges than in the centre, and its thickness increases with the degree of correction. But with a thinned lens, you can reduce its thickness by up to 40%** compared to an ordinary lens. Some frames make it easier to hide this unsightly thickness: a reasonably sized frame will allow the optician to trim the thickest edge of the optical lens, an acetate frame with thick edges will hide the edge of the lens.
• A thinned lens reduces the thickness of the lens, but also the optical effect that makes the eye appear smaller behind the lens. A frame worn very close to the face also helps to reduce this effect. 
• If you are very short-sighted, a frame with small lenses is recommended and a so-called pierced frame (without metal or acetate frames) is not recommended.

In any case, ask your optician for advice on the best optical (and aesthetic) solution.