Myopic Astigmatism: When, Why It Appears, and How to Correct It

The technology we currently use has many advantages, but it also comes with some disadvantages. One of the most important refers to eye health or, more precisely, to the conditions it causes. When we are not genetically programmed to inherit certain eye diseases, harmful habits are the ones that cause them. This is also the case with astigmatism.

There are several types of astigmatism, with myopic astigmatism being quite common today. What is it, how do we acquire it, but most importantly, how can it be corrected? It is a refractive error that occurs in both children and adults. The only way to diagnose it is through an ophthalmological consultation.

The article below presents in detail the types of astigmatism, how myopic astigmatism compares to normal vision, and how it can be treated.

Astigmatism – Definition and Types

Astigmatism – what is this condition we hear about more and more often? It is an eye condition that presents as a refractive error caused by the deformation of the cornea or lens. These are some of the most important elements of the eye. Any problem with one of them will lead to various ophthalmological diseases.

Types of Astigmatism

Astigmatism can be classified based on several factors, dividing into:

• astigmatism that affects focus and can be corneal or lenticular;
• congenital, when one or both parents genetically transmit it to their children;
• acquired as a result of trauma, eye surgeries, or caused by other ophthalmological conditions.

Astigmatism has 3 types, each associated with other vision disorders. Thus, we can suffer from:

• myopic astigmatism;
• hyperopic astigmatism;
• mixed astigmatism.

Why does astigmatism occur? Either due to habits we adopt without realizing it, or through genetics. What are its symptoms? It depends on the type.

Can astigmatism be prevented? We have surely all heard about the benefits of carrots for vision. Carrots are rich in vitamin A, which contributes to eye health. Although it can be consumed raw, the intake of this vitamin is lower. Natural carrot juice, however, can be a better alternative as it has a much higher concentration of vitamins and antioxidants.

By opting for cold-pressed carrot juice, we can enjoy all the benefits of this tasty vegetable with proven effects on eye health. With just one glass a day, we can get all the nutrients we need to have not only better vision but also a healthier heart and even more beautiful skin.

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Astigmatism vs. Normal Vision

How do people with astigmatism see? Before making a comparison, let’s see what normal vision means. It is clear both up close and at a distance. Also, a person with normal vision will perceive objects in their actual shape, not distorted.

How does a person with astigmatism see? They:

• may have double vision;
• may have blurred or hazy vision;
• may have unclear vision up close or at a distance, when astigmatism is associated with other ophthalmological disorders.

Vision problems related to astigmatism can be much more evident at night. In fact, for adults, foggy vision at night can be the first sign that they have a problem.

Often, astigmatism is also associated with other vision problems, the most common being myopia and hyperopia. Myopia refers to difficulty distinguishing objects at a distance, while hyperopia refers to difficulty up close. What happens when a person suffers from both conditions? Myopic or hyperopic astigmatism occurs. There is also a mixed version, where a person can suffer from all three disorders.

Myopic Astigmatism – What Does it Mean?

What does myopic astigmatism mean? Its definition is quite simple; the condition is characterized by an incorrect curvature of the cornea, lens, or both. These are the two refractive components of the eye.

When suffering from myopic astigmatism, the following changes occur in vision:

• the cornea, instead of being perfectly curved, will have an oval shape, with light rays focusing at multiple points on the retina;
• the lens also takes on a different shape, which can lead to more severe forms of astigmatism.

Myopic astigmatism can be of several types. More precisely:

• simple myopic astigmatism, where focusing occurs once on the retina and once in front of the retina, which is the case with myopia;
• compound myopic astigmatism, where focusing occurs only in front of the retina, but at different points.

What is the difference between myopia and astigmatism? Although both cause blurry vision:

• myopia affects distance vision due to the image projection in front of the retina.
• astigmatism deforms or distorts distant objects due to the irregular shape of the cornea or lens.

Besides myopic astigmatism, another form of astigmatism is hyperopic astigmatism.

What is Hyperopic Astigmatism?

If myopia affects distance vision, hyperopia affects near vision. Astigmatism can also occur in hyperopic individuals, on the same basis of corneal or lens deformation.

Hyperopic astigmatism occurs when the irregular curvature of the cornea associated with hyperopia leads to the focusing of two images on the retina, causing blurry vision up close.

Like myopic astigmatism, hyperopic astigmatism also has two forms:

• simple, where focusing occurs at two points, one on the retina and the second behind the retina (the main cause of hyperopia);
• compound, where both focusing points, although distinct, are located behind the retina.

However, there are also situations where people may suffer from a combination of myopic and hyperopic astigmatism, called mixed astigmatism.

Mixed Astigmatism

This is a refractive error in which one of the ocular axes has a negative error, and the other has a positive error. If we were to consider the diopter values we would wear in the case of myopia and hyperopia, they are associated as follows:

• negative or minus diopter values are attributed to myopia;
• positive or plus eyeglass diopter values are attributed to hyperopia.

Thus, if we go to the ophthalmologist for a prescription, they will prescribe glasses with minus for myopia and plus for hyperopia.

In the case of mixed astigmatism, we will have minus diopters in one eye and plus in the other.

But why does astigmatism occur in the first place? There are several reasons for the onset of this vision disorder, related to both heredity and other external factors.

Causes of Astigmatism

The main reason leading to the onset of myopic astigmatism or other types is the deformation of the cornea or lens. This defect creates the refractive error, which leads to the formation of different images on each eyeball. When these overlap, they cause blurry vision.

Why do the cornea or lens deform? It is here that we can discuss the causes that favor astigmatism, and these are:

• eye trauma;
• untreated or improperly treated eye infections;
• other eye conditions, such as keratoconus or corneal scars;
• ophthalmological interventions.

In older individuals, the condition is often caused by lens deformation. Of course, heredity can also be a cause of astigmatism. When associated with other vision disorders, it can become myopic or hyperopic.

What does not cause astigmatism is reading up close. Nor does reading in dim light favor this condition. Instead, prolonged exposure to screens can cause refractive errors.

How does a person with astigmatism see? Regardless of whether it is an adult or a child, the disorders can manifest:

• horizontally;
• vertically;
• diagonally.

But what are the symptoms of myopic astigmatism or other types? What might make us think we have a vision problem? There are some signs that should prompt us to see a doctor for an evaluation and possible correction.

Symptoms of Astigmatism in Children and Adults

Unfortunately, myopic astigmatism affects both adults and children. While adults’ awareness of the problem can guide them to a doctor, this is not the case for children. The symptoms of this condition are similar across all age groups.

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Astigmatism in Children

The most important information regarding myopic astigmatism or other types in children is that it can appear from birth. This is the case in families where at least one parent suffers from this ophthalmological disorder. Symptoms are quite difficult to detect in young children, but it is good to keep the following in mind:

• newborn screening can help determine the eye health status of babies;
• around 1 year of age, it is advisable to have the first consultation with an ophthalmologist;
• if the child is healthy, check-ups should be done annually.

For older children, they will have the same symptoms as adults, namely:

• eye discomfort;
• a sensation of a distorted visual field;
• blurry vision;
• headaches.

One of the clearest symptoms of astigmatism in children is squinting or frowning, which can temporarily improve vision.

Adults with myopic astigmatism or other types can have similar symptoms.

Astigmatism in Adults

The vision of adults with astigmatism can present several symptoms. In younger individuals, the disorder often manifests in the following ways:

• double or blurry vision;
• headaches or cephalalgia;
• a feeling of eye fatigue and discomfort;
• squinting while reading or engaging in other activities that require clear vision.

In addition to these, myopic astigmatism puts a significant strain on the eyes at night. Furthermore, individuals suffering from this disorder have difficulty adapting to darkness.

One or more of the above symptoms should prompt us to see a doctor as soon as possible.

Myopic Astigmatism and its Correction

Vision is most affected when it comes to myopic or hyperopic astigmatism, which is why seeing a doctor is very important. The ophthalmologist will determine if we have astigmatism. When we are already under a specialist’s care for this condition, regular check-ups are mandatory. Why? Because depending on the astigmatism values, correction may not be necessary.

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How Myopic Astigmatism is Diagnosed

During the specialist consultation, the ophthalmologist will consider family history but will also perform specific tests. Thus, the overall health of the eyes will be evaluated, as well as the shape of the cornea and lens. The doctor will also test visual acuity up close and at a distance. This way, they can determine if the astigmatism is myopic, hyperopic, or mixed.

After the diagnosis is established, correction of astigmatism can proceed, if necessary.

Correction of Myopic Astigmatism

Physiological astigmatism with values between 0.50 and 0.75 diopters does not require correction; any increase beyond these values needs treatment. It can consist of:

• wearing glasses;
• wearing contact lenses;
• surgical intervention.

In the early stages of myopic astigmatism, the ophthalmologist may prescribe either glasses or contact lenses. The choice is also made based on the patient’s preferences. However, for children, the former option is recommended to avoid eye infections.

The lenses used to correct astigmatism are cylindrical and can have various diopter values. If the condition is myopic or hyperopic, minus or plus diopters will be chosen, respectively. These will help correct both types of refractive errors. Regarding astigmatism, the cylindrical lens has the role of changing the projection of the light ray on the cornea. Thus, the focus will no longer be double.

If the condition progresses, the ophthalmologist may recommend surgical correction. This is performed with different types of lasers, is minimally invasive, and has the advantage of being able to permanently correct astigmatism.

In conclusion, astigmatism is a vision disorder that can affect both children and adults. The elements it affects are the cornea or the lens. It often appears due to other problems, such as myopia or hyperopia. The main causes of its onset can be both genetic and external, with untreated conditions being a frequent reason. Fortunately, myopic astigmatism or other types is a condition that can be corrected. Following a specialist consultation, the ophthalmologist may recommend glasses or contact lenses. In advanced cases, laser surgery can help permanently correct vision.

References:

https://www.mayoclinic.org/diseases-conditions/astigmatism/symptoms-causes/syc-20353835
https://www.mayoclinic.org/diseases-conditions/astigmatism/diagnosis-treatment/drc-20353838

https://www.aao.org/eye-health/diseases/what-is-astigmatism

https://www.nhs.uk/conditions/astigmatism/

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