Table of Contents
Astigmatism is a vision disorder that is widespread in the world, and the diagnosis and treatment of this disorder has greatly accelerated in Turkey.
A glimpse of the eye and refractory circles
To understand more about astigmatism, we must understand the refractive system more.
Vision occurs when light enters the eye through the pupil. With the help of other important structures in the eye, such as the iris and cornea, the right amount of light is directed toward the lens, which directs the light onto the retina.
The iris controls the amount of light entering the eye by narrowing or dilating the pupil.
The light-refracting structures in the eye are: the cornea and the lens, each of which has an anterior and posterior surfaces.
The cornea is the outer, circular, transparent part of the front of the eyeball. It is devoid of vessels with a lot of pain receptors. so It is highly sensitive to pain. The lens is a transparent structure located behind the pupil within a thin transparent capsule.
Just like the lens in a camera, the lens in the eye "refracts" (bends) the light incoming on it to optimally fall on the retina.
The retina is made up of millions of specialized visual cells known as rods and cones, which work together to convert the image or light falling on the retina into electrical energy, which is sent to the optic disc and then transmitted via electrical impulses along the optic nerve to be processed by the brain and we get The image of the body in its correct position and size.
What is Astigmatism?
Astigmatism is a common eye disorder or error in the curvature of any of the refractive surfaces of the eye that results in blurry or unguided vision.
In astigmatism, the cornea is not round, meaning that its surface is not spherical. Most people have a certain degree of astigmatism, even if they do not feel a defect in their vision.
There are several ways to classify astigmatism based on several factors:
According to the structure responsible for the defect
- Corneal astigmatism: The defect is on one of the surfaces of the cornea.
- Lenticular Astigmatism: The defect is on one of the surfaces of the lens.
The defect can also be in both structures and in their anterior or posterior surface.
Based on longitude or eye axes
The eye consists of several meridians. To explain more, we assume that the front of the eye is a clock face or a circle whose center is the middle of the pupil, and each meridian connects two different numbers (such as the diameters in a circle), and that the main meridians are two lines: one of them connects between three and Nine o'clock and the other one connects six o'clock and twelve o'clock.
In astigmatism, the flattest and most convex (sharpest) meridians are the Principle meridians.
Understanding meridians is essential when talking about the different types of astigmatism.
According to these lines, astigmatism is divided into:
Regular Astigmatism
In this case, the main meridians are perpendicular, and the refractive force of the cornea is constant in each of the orthogonal axes, and this type is the most common type of astigmatism.
Regular astigmatism can be broadly divided into:
With-the-rule Astigmatism
Common in children where the refractive force of the vertical meridian is greatest and most convex (severe) and remains close to 90°.
Against-the-rule Astigmatism
The horizontal meridian remains close to 180° and the refractive force is greater than the vertical axis. Against-the-rule Astigmatism
is common in the elderly.
Oblique Astigmatism
Oblique astigmatism is diagnosed if the principal meridians are not at 90° or 180°. Here, the shape of the eyeball resembles a tilted American football, with the principal meridians located between 30° and 60°, 120° and 150°.
Regular astigmatism can also be divided based on the defect in vision that occurs (caused by a difference in refractive force in the orthogonal axes and not in the same axis):
Simple regular Astigmatism
It means that one of the axis of the cornea brings the focus of the image on the retina, while the other axis brings it in front or behind the retina, meaning that this type of astigmatism is not accompanied by myopia or hyperopia.
Compound regular Astigmatism
In this type, the patient suffers from hyperopia or myopia, where both meridians focus the image in front of (myopia) or behind (hyperopia) the retina.
Mixed regular Astigmatism
In this case, one of the two axes focuses the image in front of the retina and the other behind the retina.
Irregular Astigmatism
The principal meridians are not orthogonal and the refractive force of the cornea is different along the same axis.
It is uncommon compared to the regular type and is often seen in external eye injuries as a result of trauma or surgery.
We note that the classification of astigmatism (astigmatism) is complex and we can say that each patient has his own classification, but these classifications were designed to facilitate matters, lay the groundwork for the treatment plan, and then amend it.
Astigmatism Causes
Until now, doctors do not know the reason for the different shape of the cornea or lens and its curvature in people in the normal state.
As well as in the case of astigmatism, the cause is not clearly known.
The condition may be present at birth, which indicates the significant role of genetics in this disorder.
Astigmatism may also result from an eye injury, eye surgery (such as surgery to implant an artificial lens).
or about a condition known asKeratoconusWhich not only leads to a thinning of the cornea, but also becomes a conical shape and leads to a refractive defect.
This condition leads to a severe degree of astigmatism, which causes the patient's vision to be impaired, and this weakness cannot be completely corrected using glasses, and in many cases, a corneal transplant is required.
Astigmatism can also occur due to the pressure of the eyelids on the cornea or the constant rubbing of the eyes (we advise not to do this) and does not result as many think from bringing the book close to the eyes while reading or from reading in dim light.
Astigmatism is usually associated with nearsightedness or farsightedness and together they are called refractive disorders.
Symptoms of Astigmatism
Astigmatism symptoms vary according to the severity and types of astigmatism. Symptoms often include:
- Blurred vision or distorted vision at all distances.
- headache;
- Difficulty seeing at night (difficulty driving at night).
- Eyestrain and Irritation.
- Long stare until the vision becomes clear.
- Astigmatism affects the depth of vision, determining the distance and clarity of the true shape of objects, and the patient can feel out of balance.
Astigmatism in children can cause a lazy eye.
Methods of diagnosing Astigmatism in Turkey
Methods for diagnosing astigmatism in Turkey have developed greatly, and the periodic examinations that are conducted have helped many people to solve a problem that many overlooked.
This is especially important for children, where they do not complain of a defect in their vision, either because they cannot or because they think that it is the normal state. It is necessary and even inevitable that periodic examinations be made for them because astigmatism affects the degree of their production, participation and interaction in school and at home, and their educational achievement.
Adolescents should also be investigated for the presence of a disease (keratoconus).
Usually Various tests Determine the degree of astigmatism and what is the best method of treatment or lenses that should be used.
At first, the doctor performs a routine eye examination, and in the event of an abnormality, more accurate diagnostic methods can be used.
Of the tests or devices used we mention:
Visual acuity test
In this test, your doctor will ask you to read the letters or point them to a chart at a specific distance to determine how well you can see the letters.
Refraction test (how the eye refracts light)
A visual test that uses a machine called a phoropter.
The device contains multiple corrective glass lenses with different strengths. Your doctor will ask you to read a chart while looking at the lenses that the doctor changes to fit your vision.
Ultimately, it will be decided which lens will best correct your vision and astigmatism.
Keratometer
It measures the degree of curvature of the cornea, in which light is focused on the cornea, and it measures the reflected light and how it is reflected to determine the curvature of the cornea.
This test is important for obtaining appropriate lenses and for differentiating normal astigmatism from disease-induced astigmatism.
Corneal Topography
It helps to obtain more information about the topography, curvature and shape of the cornea to understand the astigmatism of the eye in more detail and to choose the appropriate treatment for the astigmatism.
To inquire about more diagnostic methods or symptoms of astigmatism, do not hesitate to contact us, Bimaristan Center answers any questions about treatment in Turkey.
Astigmatism treatment in Turkey
Recently, methods of treating astigmatism have developed in Turkey, and the devices and methods used have diversified to suit the different types of visual defects, the different degrees of astigmatism, and the severity of the defect and symptoms for people with it.
The condition can be mild and asymptomatic and does not require any treatment.
The symptoms can also be annoying to the patient and affect his daily life and production, and then the doctor should be consulted to determine whether the patient has astigmatism or not and how to treat it.
The main treatment for astigmatism is the correcting lenses, whether as eyeglasses or as contact lenses, these lenses correct the majority of cases of astigmatism.
It was thought that the contact lenses used in the treatment of astigmatism are rigid contacts, but now another type of lens has been developed called toric contacts, which are small soft lenses.
Regular lenses only have one strength, but toric lenses have two: one for distance vision and one for astigmatism.
Rigid contact lenses remain the best option in severe astigmatism conditions.
In contact lenses, the field of vision is wider compared to glasses, and they are more suitable in practical life, but they have several disadvantages, such as infections due to neglect of hygiene and health rules, and they may not be suitable for all patients.
Other treatment methods include:
Orthokeratology
It is called an “ortho-k” acronym, and the doctor prescribes a hard contact lens that a person with astigmatism wears when sleeping, and these lenses straighten the shape of the cornea.
This operation is not intended for a curative treatment of astigmatism, but rather a temporary treatment, and the problem may return if these lenses are discontinued.
Surgery
There are several surgical methods for the treatment of astigmatism, most of them using lasers, and they are often definitive curative treatments, but they may contain some problems and complications, and these treatments include:
LASIK
In laser in situ keratomileusis A small flap is created in the cornea using small, fast pulses of laser, then the flap is folded back and laser targeting is used to reshape the cornea.
The flap is then returned to its place, where it adheres naturally.
lately Laser treatment of eye disorders has evolved significantly in Turkey and achieved high rates of recovery and success.
Photorefractive keratectomy PRK
Photorefractive keratectomy in which the superficial epithelial layer of the cornea is removed from the patient’s eye by a brush or a certain medical instrument, then the laser is directed to reshape the cornea. After the operation is completed, the doctor places a contact lens over the cornea until its epithelium grows again.
Corneal finishing RK
This process was dispensed with in the previous methods due to its many complications and inaccurate results.
We may need a new corneal transplant if it is badly damaged, which was fully explained in Corneal transplantation in Turkey.
These operations can be performed on patients who are in good health and who are qualified for surgery.
Everyone should have regular checkups to ensure the health of their most important sensory organ and to correct any malfunctions in it.
See a specialist from Bimaristan center orcontact thembecause you can have astigmatism and you don't know it.
