Today, we are here to discuss a common refractive error – nearsightedness. Other refractive errors are astigmatism and hyperopia, among others.
Maybe you find it hard to focus on distant objects. Or perhaps you experience headaches and dry eyes.
All of these signs can point to the common vision problem that it is myopia. If you want to learn more about it, do stay with us.
In today’s article, we will cover everything that you need to know about one of the four refractive errors known to man.
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What is Myopia?
Myopia is the medical term that describes the issue of nearsightedness. It is a common vision problem. As much as 30% of the American population is struggling with nearsightedness. Despite being a common vision issue, the good news is that myopia is still treatable.
This eye condition causes the eye to see the nearby objects clearly. But, the issue occurs when one looks at faraway objects which tend to appear fuzzy. It is also referred to as blurred distance vision.
Over the years, doctors have determined different types of myopia. Depending on the age at which nearsightedness first occurred, we differ three types.
Pathological myopia
Pathological myopia typically develops before the age of 6. It is also known by the name of degenerative myopia. What happens is a deformation of the eye, which causes stress to the retina. This often leads to further issues affecting the retina. We will talk more about degenerative myopia later in this article.
School-age myopia
A case of school-age myopia usually develops between the ages of 6-18. This type of myopia is more common among individuals with high IQs and those who spend more time reading. In the majority of patients, stabilization is expected to happen in their late teens.
Adult-onset myopia
As the name suggests, adult-onset myopia occurs at an older age. There are two types, with those being early and late-adult onset myopia.
A patient with early adult-onset myopia develops the first symptoms around the age of 20 to 40 years old. As for late-adult onset myopia, the first symptoms take place after the age of 40.
The severity of myopia is described according to the power needed to provide the proper vision correction. That is measured in diopters. And so, again, we have three types of nearsightedness.
- Mild myopia is also known as low or simple myopia. The eye is otherwise healthy. With the use of glasses or eye lens, clear vision is possible. In this case, myopia does not exceed -6.00 diopters and is usually of -3.00 diopters.
- Moderate nearsightedness refers to myopia between -3.00 and -6.00 diopters.
- High myopia describes a case of myopia that exceeds -6.00 diopters. A patient with high myopia is more likely to have a retinal detachment. High myopia is the most severe case of this eye issue.
Some patients have a measurement of -10 diopters and more. These patients are at risk of developing what is known as myopic macular degeneration.
Myopic macular degeneration, or myopic maculopathy, resembles another common eye disease called age-related macular degeneration.
This eye disease tends to worsen over time. It can go as far as to cause permanent blindness, typically among people over the age of 60. This eye disease is caused by the wear down process of a specific part of the retina called the macula, hence the name.
In the case of myopic maculopathy, a new blood vessel develops at the macula itself. This causes bleeding and scarring to take place. A specific area of a pigment called Fuchs spot develops.
Other possible types of myopia are:
- Pseudomyopia – The cause behind pseudomyopia is a spasm of the accommodation system. The patient experiences blurry vision when looking at a distant object.
- Induced myopia – Induced or acquired myopia results as a side-effect of various medications. Other health issues, such as an increase in glucose levels and oxygen toxicity, can contribute to the occurrence of induced myopia as well.
- Nocturnal myopia – Nocturnal myopia refers to the eyes’ tendency to become near-sighted in low-illumination areas. Their long-distance vision seems out of focus.
- Instrument myopia – Scientists tend to experience instrument myopia. The reason is the prolonged period of time that they spend looking at a microscope.
Other types besides these do exist as well. Now let’s discuss the characteristic symptoms of this common vision problem.
What are the Symptoms of Myopia?
One of the most obvious symptoms of myopia is blurred vision. The myopic eye struggles to focus while looking at distant objects.
Adults often report on not being able to see a street sign in the distance while driving. For children, the most commonly reported symptom is not being able to see what their teacher is writing on the blackboard.
It is not uncommon for other symptoms to be present as well. The list of common symptoms also includes:
- Eye fatigue
- Squinting
- Frequent headaches
- Eye strain
- Dry eye, etc
With the use of lens or eyeglasses, these symptoms tend to go away. This means that the patient is supposed to continue using corrective lenses or eyeglasses for the rest of their life. Another option is getting eye surgery. But we will learn more about the treatment options in a while.
Although it is unlikely that myopia will lead to additional eye issues, there is a possibility of getting worse with age. This is especially probable in the case of high myopia.
Potential complications include retinal detachment, glaucoma, and cataract, among others. Blindness is possible, but not likely to happen unless it is a case of pathological myopia.
What Causes Myopia?
There are two explanations behind myopia. Either the cornea is too curved or the eyeball is too long.
These abnormalities cause the light to stop in front of the retina, instead of stopping on it as it does in healthy individuals. Because the light is unable to focus properly on the retina as it is supposed to, the patient experiences a blurry vision.
Ophthalmology still does not have the answer as to what causes myopia. However, there have been a few suggestions made over the years. These factors could contribute to the abnormalities regarding the cornea or the eyeball, thus causing myopia.
Genetics seems to play a pretty significant role in the development process of myopia. Children with myopic parents have a greater tendency to develop nearsightedness themselves. The risk is even higher in case both parents are nearsighted.
Some health issue such as cataract and diabetes often leads to myopia as well. These patients are recommended to visit an eye doctor at least once a year. A regular eye exam can help detect myopia in its early stages.
Visual stress seems to be an important risk factor. Doing detailed work that requires a lot of focusing, such as reading and/or using the computer, can lead to myopia.
Treatment of Myopia
Myopia is diagnosed by performing a comprehensive eye exam. The eye doctor will use different instruments and lens to test out your close-up and distance vision. He will check your general eye health as well. Eye drops will probably be used to help dilate the pupils as a part of the testing.
- Lens/ Glasses: The goal of the treatment is to help the light focus on the retina. That is accomplished by either using corrective lens/eyeglasses or doing refractive eye surgery. Eyeglasses are easy and simple to use. Some patients prefer a contact lens, especially the soft lens, which can be more convenient to use.
- Orthokeratology: This is a popular option, as well. It is usually recommended for individuals with mild myopia. This corneal refractive therapy involves the use of different rigid contact lenses. The goal is to reshape the cornea to make it resemble a normally-shaped cornea. The lenses are worn for several hours a day. As the shape of the cornea flattens out, the time is reduced.
- Surgery: Others decide on getting surgery instead. Surgery can significantly reduce and even eliminate the need to use eyeglasses and corrective lenses. This treatment method can also prevent further myopic progression and improve the patient’s quality of life. In most cases, the surgery is done by using a laser.
- Laser eye surgey: There are a couple of laser eye surgery methods that can be done. One of the most popular methods is photorefractive keratectomy. During this procedure, after using atropine eye drops to widen the pupils, the eye doctor uses a laser to remove a layer of the corneal tissue. This will help flatten the cornea, thus allowing light to focus closer to the retina.
The result is a clear close-up and distance vision. The whole procedure takes around 20 minutes – 10 minutes per eye. It is a much more expensive option, but it is still commonly done among myopic patients. It is also painless and recommended for several different types of myopia.
Controlling Myopia
Besides using eyeglasses/lenses and getting the surgery done, other methods can help prevent further myopia progression. Researchers and doctors have been working hard to develop myopia management methods, many of which have proven quite useful.
Atropine, apart from being used for eye surgery, is often used for myopia control. Despite the exact mechanisms remaining unknown, myopia progression can be slowed down by using atropine drops.
Increasing the time spent outside proves to be quite helpful as well. Sunlight works to change the molecular structure of the cornea, thus maintaining its healthy shape. By doing so, the UV rays help slow down myopic progression.
Degenerative myopia
While sometimes myopia can go unnoticed, other times, it can lead to a more severe issue. Degenerative myopia or progressive myopia is a degenerative eye condition. Doctors describe this condition referring to the back of the eyeball breaking down. Luckily, such severe cases of myopia are still rare.
The majority of cases are hereditary, with the first symptoms taking place in early childhood. As much as 2% of the American population is affected by progressive myopia. This eye issue is listed as the number one cause for legal blindness in the United States. On a global level, degenerative myopia affects up to 3% of the population.
Other than the elongated axial length, yet another hallmark is present in this case. Posterior staphyloma represents an outward protrusion of the layers of the so-called posterior eye globe. Both environmental and genetic factors seem to play a role in the development of degenerative myopia. Also, women tend to have a higher risk as compared to men.
Many patients are asymptomatic as the condition slowly progresses. Blurred vision and metamorphopsia are two of the most common symptoms. In terms of pathological myopia, no topical pharmacotherapy nor surgery has shown impressive results.
Researchers are still working on finding a treatment method that would prove useful. In the meantime, the typical treatment methods that we discussed before are recommended.
Conclusion
One of the most common refractive errors is myopia or nearsightedness. This issue prevents the eye from focusing on faraway objects as it should. Thus, the patient struggles with blurry vision, squinting while looking at distant objects and experiencing headaches.
The most severe form of myopia, pathological myopia, threatens to cause complete, permanent blindness. Unfortunately, children are not spared from this issue.
We now see more and more young children wearing eyeglasses and soft lenses to help correct the cornea’s curvature that is causing this issue in the first place.
