Myopia – Reduced distance vision
Myopia, or nearsightedness, is the most common vision disorder worldwide. It results in a decrease in distance vision that gradually worsens during growth. Near vision, however, remains perfectly clear. Optically, myopia means that the eye is too "strong" or too "long," in which distant images are focused in front of the retina. It is corrected with glasses, contact lenses, or refractive surgery.
What is myopia?
Myopia is a refractive error resulting in a permanent decrease in distance vision.
It reflects an eye that is too strong, that is to say, too long.
It can be corrected medically by wearing optical correction (glasses or contact lenses) or surgically (refractive surgery)
It affects 20 to 25% of the French population and its incidence is constantly increasing.
This is a focusing disorder of the eye, not an eye disease.
What is a refractive error?
Refractive errors occur when your eye does not focus light correctly onto the retina. This focusing is called refraction (curvature).
In order for you to see clearly, light rays must pass through the cornea and the lens. The cornea and the lens adjust the light so that it falls on the retina.
The retina transforms light into signals that travel to the brain and become images. If there is a refractive error, the shape of your cornea or lens prevents light from bending correctly. When light is not focused on the retina as it should be, your vision is blurry.
Types of myopia
Myopia in children
Myopia in children can be inherited. If a parent is myopic, their child has a high chance of also being myopic.
Myopia is often discovered in children between 8 and 12 years old.
During adolescence, when the body is developing rapidly, myopia can worsen.
Between the ages of 20 and 40, there is generally little change.
High myopia and low myopia
Mild myopia is called low myopia. High myopia is called pathological myopia.
Mild myopia usually stabilizes between 20 and 30 years of age, while severe myopia can progress throughout life.
We speak of high myopia when the eye measures more than 26 mm or when the correction exceeds -6 diopters.
People with myopia (nearsightedness) are at a higher risk of retinal detachment. This is a separation of the sensory membrane that lines the back of the eye. Retinal detachment is a serious eye emergency that can lead to blindness.
Patients with high myopia may also be at a higher risk of developing glaucoma and cataracts.
Symptoms of myopia
The main signs and symptoms of myopia are:
Decreased distance vision: difficulty seeing distant objects, such as road signs or the blackboard at school.
Squint to see clearly.
Eye strain.
Headaches – Worsened in case of overcorrection.
These symptoms may become more evident when children are between 8 and 12 years old.
Causes of myopia
Myopia is caused by a cornea that is too strongly curved or an eye that is longer than normal.
In both cases, the light rays are focused in front of the retina and not on it.
Heredity is a recognized risk factor for myopia.
Some studies have also shown that increased close work and decreased time spent outdoors during childhood increase the risk of myopia.
Diagnosis of myopia
Your ophthalmologist can diagnose myopia as part of a comprehensive eye exam. They will use a standard vision test and ask you to read letters on a chart placed across the room.
Your doctor will use certain examination devices to determine the cause of the myopia.
An automatic refractor projects a special light into your eyes, which is reflected onto your retina. This allows for an approximate determination of whether a person is nearsighted or farsighted.
A phoropter allows the ophthalmologist to precisely adjust the degree of refractive error you have. It also helps determine the appropriate prescription to correct your vision.
Myopia treatment
There is no single best way to correct myopia. The most suitable correction for you depends on your eyes and lifestyle. Discuss your lifestyle with your ophthalmologist. Together, you can decide on the most effective correction for you and your needs.
Glasses and contact lenses
Glasses or contact lenses are the simplest and most common ways to correct vision problems caused by refractive errors. They adjust your vision so you can see more clearly.
The ophthalmologist will test your vision and, if necessary, give you a prescription for glasses or contact lenses. Over time, you will need new prescriptions as your eyes change.
There are many options to consider when buying glasses or contact lenses. Discuss with your ophthalmologist and optician the lens choices that can meet your vision and lifestyle needs.
Refractive surgery
In most cases, this type of surgery reshapes the cornea using a laser to adjust how light passes through it. Here are some of the most common procedures:
LASIK
PRK and trans-PRK (contactless surgery)
SMILE
Phakic implants were developed to correct myopia when laser treatment is not an option. The procedure involves placing a permanent lens in the eye, just behind the pupil. It is a more invasive procedure than laser surgery, requiring a pre-operative assessment and close monitoring.
Like any surgery, refractive surgery carries risks of complications and possible side effects. For example, after undergoing refractive surgery, you may experience glare or halos around lights, or poor night vision.
Discuss your vision needs and expectations with your ophthalmologist. Together, you can explore the options available to improve your vision.
Slowing down myopia
Some therapies have shown effectiveness (often relative) in slowing down or even stopping the progression of myopia in children. These include:
You may have heard of a procedure called orthokeratology or ortho-k for treating myopia. It uses a series of hard contact lenses to slowly flatten the cornea and reduce myopia.
This involves wearing hard contact lenses every night. This method has been associated with a high risk of serious and dangerous eye infections.
The improvement in vision is temporary. When you stop using the lenses, your cornea returns to its original shape and the myopia reappears.
Since 2020, it has been possible to market corrective lenses, reproducing certain principles of orthokeratology.
These are glasses that correct myopia with several focusing zones on the retina.
This principle would slow its progression. The glasses have the advantage of not presenting the infectious risk of night lenses.
Low-dose atropine (0.01%) has emerged as an effective approach to slowing the progression of myopia in children and adolescents.
It is used daily and recent studies seem promising. It also appears safer because it avoids the complications of orthokeratology.
However, the deployment of low-dose atropine is limited at the moment.