Genetics plays an important role in myopia. However, it is not the only factor. Looking at nearby objects for long periods of time and lack of outdoor exposure can also contribute.
Myopia, also known as myopia, is a visual impairment that causes a person to see distant objects less clearly.
Many genetic factors can cause myopia. For example, if one or both of a person’s parents have myopia, they have a greater chance of developing the condition.
This article discusses genetic and non-genetic factors in myopia, as well as how they interact.
Yes, genes play a significant role in myopia or myopia. Studies so far have discovered more than 200 genes that have links to myopia. Researchers believe that each of these genetic factors contributes a small amount to the development of myopia.
There are also more than 200 specific genetic conditions that can cause myopia as one of the symptoms, but most of them are rare. Some examples include:
- Stickler syndrome
- Marfan syndrome
- Cohen syndrome
- retinitis pigmentosa
- cone-rod dystrophy
The terms “dominant” and “recessive” describe how a specific gene passes from parent to child. In dominant genetic conditions, only one of a child’s parents needs to have the gene for the child to have a chance of inheriting it. In recessive conditions, both of the child’s parents must have the gene.
Myopia is generally neither a dominant nor a recessive trait. In most cases, it occurs due to a mix of genetic and environmental factors, not just one gene.
The exception is when a person inherits a specific genetic condition that causes myopia as a symptom. When this occurs, the inheritance pattern can be dominant, recessive, or X-linked, depending on the condition.
An X-linked inheritance pattern means that the gene that causes myopia is on the X chromosome. Men have only one X chromosome, while women have two, so these genetic conditions affect men more often.
If a person has myopia due to a specific genetic condition, the gene that causes it may come from the father or mother, or both, depending on the condition.
For example, X-linked congenital stationary night blindness is a genetic condition that is more likely to come from the mother.
This is because women always contribute an X chromosome during conception, while men can contribute either an X or a Y chromosome.
However, most genetic conditions that directly cause myopia are rare. In most cases, myopia occurs due to a combination of genes that can come from either the female or male parent.
If someone has an immediate relative with myopia, such as a parent, they themselves have a greater chance of developing myopia.
Yes, environmental factors can also contribute to myopia, especially in people with a genetic predisposition.
In fact, scientists believe that the global increase in myopia is largely due to changes in people’s lifestyles. One estimate predicts that, by 2050, almost half of the world’s population will have myopia.
Some of the risk factors include:
- More education: The longer a person spends in education, the more likely they are to develop myopia. Previous studies have shown that people who enter higher education are at double the risk of myopia than people who don’t.
- Upcoming work: Nearwork is any work that requires focusing on an object up close. As more people started working in offices, using computers, and spending time on devices, the rate of myopia increased. This may also explain why education is a risk factor, since reading and writing are close types of work.
- Lack of outdoor exposure: When people spend long periods of time indoors, their eyes do not need to focus on distant objects. This can increase the risk of myopia.
Some people have myopia from birth. In others, myopia does not develop until adolescence. Doctors often find myopia in children between the ages of 8 and 12.
For most people, myopia does not reverse or improve with age. Many people with myopia experience a worsening of their symptoms during adolescence into adulthood, but little change between the ages of 20 and 40.
Some people experience improvement in adulthood, but this is not common.
Myopia has no cure. However, there are treatments that can slow its progression or improve vision.
Low-dose atropine eye drops may slow the progression of myopia in children and adolescents with myopia. There are also special contact lenses for children that blur peripheral vision, which can have a similar effect.
Most people treat myopia by using glasses or contact lenses, which adjust the way light enters the eyes. There are also surgical options to permanently correct a person’s vision. These procedures use lasers to reshape a person’s cornea.
However, not everyone is eligible for laser eye surgery procedures. According to the American Academy of Ophthalmology (AAO), candidates for laser eye surgery will:
- be at least 18 years old
- did not have several changes in ophthalmological prescription in the previous year
- have thick, healthy corneas, as well as good overall eye health
It is not always possible to prevent myopia, but there are steps people can take to try to avoid it. The first step to doing this is spending more time outdoors, according to the AAO.
In summary, myopia is often caused by genetic factors. However, environmental factors such as proximity and lack of outdoor exposure can interact with these genetic factors to cause or worsen its development.
Researchers largely agree that the continued increase in the global prevalence of myopia is primarily driven by these environmental factors. As people undertake longer periods of telecommuting and spend less time outdoors, the global prevalence of myopia increases.