Astigmatism
What is astigmatism?
Astigmatism is a condition characterized by unclear and blurred vision due to the irregular shape of the cornea, which represents 1/6 of the surface layer of the eye, or as a result of uneven surface of the eye lens.
The uneven shape of the cornea or lens prevents light entering the eye from focusing properly on the retina – the light-sensitive surface on the inside of the eyeball.
As a result of this abnormality, those affected by astigmatism see blurred and blurred vision at any distance.
Astigmatism is a very common visual abnormality. Most people have some degree of astigmatism. The initial stages of astigmatism usually do not affect vision and do not require treatment.
Astigmatism is very often seen in patients with vision abnormalities such as nearsightedness (myopia) and farsightedness (presbyopia). And these visual disturbances have a common medical name, and that is refractive errors, because they affect the way the eye refracts the light entering it.
How does it occur?
The specific cause of astigmatism is unknown. This abnormality may be hereditary and present from birth and may change as the child grows, gradually subsiding over time or worsening and deepening the complaints.
A thorough optometric examination also includes an astigmatism test. Depending on the stage of the anomaly, the eye doctor prescribes glasses or contact lenses that correct the astigmatism by changing the way light enters the eyes.
Another way to treat astigmatism involves a modified procedure called Orthokeratology.
It is a painless, non-invasive procedure that consists of wearing a series of specially designed hard contact lenses that gradually remove the irregularities on the surface of the cornea that are the cause of the refractive error.
Laser surgery is also a possible way to treat astigmatism. The shape of the cornea is changed by removing a small amount of eye tissue. This is done with a highly focused laser beam on the surface of the eye.
What are the causes of astigmatism?
In a healthy human eye, light passes through the cornea and lens, which work together to focus light on the retina, the thin layer of tissue at the back of the eye that contains millions of light-sensitive cells.
The cornea and lens of a healthy eye have a symmetrical and regular shape, which allows light to be refracted evenly.
This means that all light rays entering the eye are focused at a single point on the retina, resulting in clear and detailed vision.
However, in astigmatism, the shape of the cornea or lens is slightly deformed. This can be due to genetic factors, trauma to the eye or certain eye diseases.
Instead of being perfectly round, the cornea or lens may be more convex in one direction than another.
This uneven shape changes the way light is refracted as it enters the eye. Instead of focusing at one point on the retina, the light is focused at several different points.
This results in distorted or blurred vision, which can be particularly noticeable when looking at distant objects or in low light.
It is important to remember that if you notice a change in your vision, such as blurred or distorted vision, it is important to see an eye doctor for an examination and diagnosis.
How is astigmatism diagnosed?
Astigmatism is a visual disorder that can be diagnosed through a comprehensive eye examination. This exam usually includes a series of tests that help the eye care professional understand exactly how your eyes focus light.
This is important because astigmatism can change the way your eyes refract light, leading to blurred or distorted vision.
One of the main tests used to diagnose astigmatism is the refraction test. In this test, the eye doctor uses a device called a phoropter to determine what glasses or contact lenses are needed to correct your vision.
The phoropter has different lenses that can rotate in front of your eyes as you look at letters or numbers on a distant sign. Your doctor will change the lenses until he finds the combination that allows you to see the most clearly.
In addition to the refraction test, your eye doctor may use other tests to diagnose astigmatism.
This may involve using a device called a keratometer, which measures the curvature of the front surface of your cornea. This helps the doctor determine whether the shape of your cornea is causing your astigmatism.
Once a diagnosis of astigmatism has been made, your treatment may include wearing glasses or contact lenses that are specially designed to correct the way your eyes refract light.
In some cases, a surgical procedure, such as LASIK, may be recommended to reshape the cornea and correct astigmatism.
How is astigmatism treated?
People with astigmatism have several options to regain clear vision. These include:
- Glasses;
- Contact lenses;
- Orthokeratology;
- Laser and other surgical procedures.
Glasses are the preferred treatment for astigmatism. They are a special cylindrical lens to compensate for astigmatism. And only one type of lens is enough to provide clear vision at all distances.
Some people prefer contact lenses to deal with astigmatism because they give them a wider angle of vision.
However, because contact lenses are worn directly on the eyes, they need regular cleaning and care to maintain eye health, and standard contact lenses are soft and not suitable for treating astigmatism, as they perceive the shape of the eye.
Orthokeratology involves placing a series of hard contact lenses that change the surface of the cornea, but this method does not achieve a permanent improvement in vision because after they are removed, the vision returns to its original state of blurred vision.
Astigmatism can be corrected by reshaping the cornea using a highly focused laser beam of light. Two of the most commonly performed procedures are photorefractive keratectomy (PRK) and laser in-situ keratomileusis (LASIK).
Both procedures allow light to focus on the retina by changing the shape of the cornea.
People with astigmatism have a wide choice of ways to correct their vision problem. In consultation with their eye doctor, they can choose a method that best meets their needs.
