Astigmatism is a visual pathology that leads to a significant decrease in visual acuity. This defect is a type of ametropia, that is, anatomical changes that disrupt the normal refraction of the ray, which must be focused on the retina. In the presence of this disease, the child not only does not have the ability to clearly distinguish objects that are near or far, but also perceives them in a distorted form.
Lack of treatment for astigmatism can provoke the development of other visual pathologies, and in especially severe cases, lead to disability. What are the types of astigmatism in children? What methods are used by modern ophthalmologists for the treatment and prevention of the disease? What is the future prognosis for a child with astigmatism?
The mechanism of development of astigmatism and its types
A group of visual disorders, which include astigmatism, are called refractive errors. These include:
- myopia (myopia);
- hyperopia (farsightedness);
- presbyopia (aging of the lens).
Astigmatism occurs in both children and adults. This is mainly a congenital defect, but the disease can also develop as a result of mechanical injury or surgery. Statistics indicate that practically 58% of the entire adult population of the Earth has astigmatism ≥0.25 D. With astigmatism, there is a change in the refractive index, sphericity and curvature of the eye components.
Also, the cause of visual disturbances can be a violation of the mechanism for aligning the eyes relative to each other, in which light rays passing through the transparent media of the eye and having parallel trajectories are focused into two different focal lines perpendicular to each other, instead of focusing on one focal point.
Not so long ago, a number of clinical studies were carried out, during which a connection was established between the process of autosomal recessive inheritance and the development of astigmatism. Due to a violation of the refractive abilities of the eye there are several types of astigmatism:
- corneal;
- lens;
- ocular (ocular).
Next, let's take a closer look at each of these types of violations.
Corneal
The cornea is one of the transparent media of the eye, which is located in front of it. In addition to its main conductive function, the cornea is involved in protecting the eye from mechanical damage and the ingress of infectious agents there.
In children with astigmatism, it usually has a slightly oval shape instead of the normal spherical shape. This anomaly leads to the fact that the focusing of light rays occurs at two points instead of one.
In modern ophthalmology, a clear understanding of the etiological factors that provoke abnormal corneal formation has not yet been formed.
It has been proven that a genetic predisposition has a certain effect on this mechanism. A child whose parent suffers from this anatomical defect has an increased chance of inheriting it. Therefore, a baby with such a family history should be examined for refractive error as soon as possible.
Corneal astigmatism can also be associated with any pathologies of the fibrous membrane of the eye, including acute and chronic inflammatory diseases, mechanical damage, keratoconus, keratoglobus, pterygium and other reasons that provoke hypertrophic changes in the structure of the cornea.
Lenticular
The lens is a kind of organic lens that sits behind the iris. Any structural damage or violation of its refractive power leads to decreased vision. Most patients with lens astigmatism have a normal corneal shape.
Often, the cause of the development of this disease becomes dislocation or subluxation of the lensthat happen as a result uneven tension distribution of the zinc ligament, which changes its spatial position. Also, this type of astigmatism can be a consequence of mechanical trauma to the eye or cataracts.
Systemic diseases such as diabetes mellitus or hypertension lead to disruption of the normal process of blood circulation in the vessels of the eyes, because of this, the shape and size of the lens are gradually deformed.
Ocular
Ocular astigmatism is quite rare among other types of congenital astigmatism. It can develop as a result of swelling of the optic nerve, pathological changes in the posterior ocular pole, orbit, or other nearby facial bones.
Clinical picture
There are several degrees of this disease, which differ depending on the level of refractive error:
- weak - up to 3 D (the most common form, successfully compensated);
- medium - 3-6 D (less common, correction or surgical treatment is possible);
- high - above 6 D (it is recorded quite rarely, it is treated only by surgery or with the help of laser correction).
The main symptoms of astigmatism are:
- blurry or distorted vision at different distances from objects;
- photophobia (increased sensitivity to light);
- frequent headaches;
- excessive eye strain (happens when you have to focus on something for a long time, for example, when reading or working at a computer);
- increased fatigue.
When making a diagnosis in young children, and even more so in infants, it is difficult to determine astigmatism, since the child cannot always notice and explain that he has begun to see worse. In such cases, the attentiveness of the parents helps out: they may notice that the baby began to squint often, and also tilt his head to the side, examining an object.
In ophthalmology, there is a special concept - "Physiological astigmatism", in which there is a weak degree of refraction disturbance (no more than 0.5 D), which makes it difficult to diagnose. It must be borne in mind that even a weak degree of development of astigmatism in a child needs treatment, since the lack of proper therapy for such a serious visual impairment can lead to serious consequences.
If a child perceives the image in a distorted form for a long time, this provokes the degradation of the entire visual apparatus (in particular, cells of the visual cortex), and this, in turn, leads to the formation of persistent amblyopia.
Treatment methods
Among all children and adolescents with astigmatism, the majority has a weak degree of refractive error, which is not always noticeable by parents at the initial stages of the development of the disease. Therefore, the child must regularly undergo preventive examinations by an ophthalmologist.
Depending on the degree of development and type of disease, an ophthalmologist may choose one of the following areas of treatment for astigmatism:
- vision correction with glasses;
- vision correction with contact lenses;
- surgery and laser technology.
Additionally, the child must periodically take a course apparatus treatment and physiotherapy... He is also shown a special visual gymnastics. Thanks to special exercises during charging for the eyes, you can not only increase visual acuity, but also avoid the development of concomitant disorders (for example, strabismus). Spectacle or contact corrections are designed to correct incorrect refraction of light.
Wearing contact lenses is undoubtedly more effective for astigmatism, since this method allows you to take into account the individual characteristics of the defects in the structure of the eyeball.
Contact correction does not provide for the presence of a vertex distance between the eye, which is 12 mm on average with spectacle correction. Constant wearing of contact lenses is advisable for mild and moderate refractive errors in children.
Correction methods by types of astigmatism
The first attempt to correct this type of refractive error was made by an Englishman George Biddel Airy in 1872. He created a 4 D minus cylindrical lens to compensate for the astigmatism in his left eye. The main quality that distinguishes cylindrical lenses from spherical lenses is that the cylinders focus the light beam into a straight line rather than a point.
Contact lenses that correct astigmatism are almost impossible to make completely cylindrical, so a spherocylindrical, or, as it is also called, toric shape is created for them. With their regular use, it is necessary to strictly adhere to all operating requirements, especially with regard to hygiene rules.
There are many types of contact lenses, depending on the design, including: hard glass-plastic, polymer gas-tight, soft silicone, etc. The rules of their operation depend on the type of specific lenses.
Lenses for the correction of astigmatism are distinguished by the presence on their surface of certain marks indicating the correct position in the eye (at a certain angle).
Methods of surgical treatment of astigmatism
The most effective method for correcting astigmatism is laser correction. At the moment, there are several varieties of it:
- laser keratomileusis (LASIK);
- super-LASIK;
- epi-LASIK;
- femto-LASIK (Intra-LASIK);
- laser epithelial keratomileusis (LASEK);
- photorefractive keratectomy (PRK).
These techniques differ in the degree of exposure and the method of processing the surface of the cornea. However, in essence, they have a common principle: with the help of a laser, the shape of the cornea is changed to spherical, taking into account the individual characteristics of the eye. Such operations can be performed not only for patients with corneal type of astigmatism, but also with lens astigmatism, since the degree of refraction of the light beam changes when correcting the shape of the cornea.
However, this procedure also has a number of contraindications:
- the presence of diabetes mellitus (since in this case astigmatism is a secondary disease and, first of all, therapy of the underlying disease is necessary);
- the presence of severe immune diseases, such as lupus, HIV, etc., (due to the high risk of complications during the postoperative period);
- treatment with certain groups of drugs (corticosteroids, some types of antibiotics, isotretinoin, etc.);
- high severity of astigmatism (above 5 D).
If for some reason it is impossible to apply laser correction to a patient with corneal refraction disorder, keratoplasty (partial or complete replacement of the cornea with an artificial or donor one) can be performed.
The refractive lens replacement procedure is widely used to correct lens-type astigmatism. Its essence consists in removing the damaged lens through a micro-incision and replacing it with an intraocular toric lens.
Myopic
As already mentioned, with astigmatism, the cornea has an irregular shape. It can be of several types, which enables ophthalmologists to classify astigmatism in more detail. Myopic (nearsighted) astigmatism in one or both eyes is a type of refractive error in which the eye is dominated by myopia.
This means that if in a healthy eye light rays, passing through transparent media, focus on the retina at one specific point, then in an astigmatic eye this happens simultaneously at several points, while some part of the "picture" is focused in front of the retina (which is characteristic for myopia), and the other on it. Also, the light beam can be focused at two points in front of the retina.
Simply put, this pathology can be regarded as a kind of synthesis of astigmatism and myopia.
Myopic astigmatism can be simple or complex. They can be differentiated during an ophthalmological examination by determining the main meridians of the eye. There are two types of myopic astigmatism:
- Plain. It is characterized by the fact that myopia is observed in one of the main meridians of the eye, and normal vision in the other. In this case, a certain part of the rays is focused on the retina (as happens in a healthy eye), and the other part is in front of it (which is characteristic of myopia);
- Complicated. Here myopia takes place in both main meridians of the eye, but it has a different degree in each of them. In this case, the rays of light are focused at two points in front of the retina.
The clinical picture of myopic astigmatism is characterized by the presence of the following symptoms:
- decreased visual acuity;
- double vision, as well as other types of image distortion;
- headache;
- lacrimation with prolonged focusing of the gaze on a specific object.
With this type of astigmatism, the child is forced to approach the object as close as possible in order to see it clearly. The "picture" can double or blur. If we are talking about mild myopic astigmatism (less than 3 D), then such symptoms may be absent. The child may not notice a decrease in vision or simply get used to the perception of a distorted image.
In this case, parents should pay attention to the fact that the child began to tire quickly after prolonged visual stress or complains of a headache.
The main cause of myopic astigmatism is hereditary factor... In rare cases, the disease develops as a result of previous injuries, operations or infectious diseases.
Myopic astigmatism can be difficult to differentiate from myopia, since the clinical picture of these diseases is quite similar. It is especially difficult to make a correct diagnosis when vision is impaired in both eyes.
If the child was not diagnosed on time, as a result of which he did not receive adequate treatment, then at an older age he may develop more serious defects of the visual apparatus, for example, such as amblyopia, or "lazy eye" - a pathology that can be corrected with great difficulty. Therefore, it is necessary to seek qualified help in the early stages of the development of the disease.
To do this, the child must regularly undergo preventive examinations by an ophthalmologist, and parents must respond in a timely manner to the appearance of any signs of decreased vision. Treatment of mild and moderate myopic astigmatism includes, first of all, the use of spectacle and contact correction, apparatus treatment, and visual gymnastics.
Additionally, instillations of medicinal eye drops can be prescribed, as well as regular intake of a complex of vitamins. Sometimes surgery may be considered by an ophthalmologist.
With myopic astigmatism of a high degree, surgery is considered the most optimal method of solving the problem. In this case, the constant wearing of glasses or contact lenses can become cause of regular headaches and dizziness... There are several methods of corrective surgery for high myopic astigmatism.
Astigmatic Keratotomy
Micro-incisions are made on the surface of the cornea in the corresponding meridian. In the process of their healing, there is a gradual change in the curvature of the cornea along the axis, which contributes to the weakening of the stronger meridian.
Photorefractive keratectomy
With the help of a laser, a kind of "polishing" of the corneal surface is performed. Due to this, its curvature changes. During the operation, the surface layer of the cornea (epithelium) is removed, other structures of the eye remain intact.
The recovery period usually lasts no more than a week. At this time, the patient may feel pain and burning in the eye, photophobia (increased photosensitivity) and lacrimation. At this time, you must wear special protective contact lenses.
Photorefractive keratectomy is not performed on both eyes at once; moreover, there is a risk of turbidity of the central optical zone of the cornea. After such an operation, vision is restored no later than six months later;
Laser keratomileusis
At the moment, this procedure is very popular. Laser keratomileusis is a very effective way to correct myopic astigmatism. Its essence lies in changing the shape of the cornea by removing its middle layers, which, unlike photorefractive keratectomy, avoids the threat of opacification of the central zone of the cornea and the appearance of pain during the recovery period.
The operation is performed with a laser. This procedure allows you to achieve the highest possible visual acuity, which in the future no need to correct with glasses or contact lenses.
Unfortunately, there is a list of contraindications and possible side effects for such manipulation. All possible risks, as well as the arguments in favor of the operation, must be discussed in detail with the ophthalmologist, which will help to make an informed decision. The results of laser keratomileusis will be irreversible.
In special cases, in the presence of absolute contraindications to the implementation of the above methods of treating myopic astigmatism, the ophthalmologist may recommend more radical methods, such as phakic intraocular lens implantation, lens replacement or corneal transplant.
Farsighted
Complex farsighted astigmatism develops when the normal structure of the corneal surface is disturbed: it becomes toric with an uneven curvature, and the eyeball acquires a slightly flattened shape. Various factors can provoke such changes in the visual apparatus. With farsightedness, or hyperopic astigmatism, the focusing of light rays is carried out behind the retina. The disease can be simple or complex.
Symptoms of hyperopic astigmatism:
- burning in the eyes;
- blurred vision;
- diplopia (double vision);
- rapid eye fatigue during various kinds of visual stress (reading, working at the computer, watching TV, etc.);
- feeling of tension in the eyes.
In most cases, the etiology of hyperopic astigmatism is associated with heredity, but it happens that the disease develops as a result of external factors.
There are several types of farsighted astigmatism:
- Simple form. Vision is normal in one of the two main meridians of the eye, and farsightedness in the other;
- Complex shape. In both major meridians of the eye, hyperopia is present in varying degrees.
In complex hyperopic astigmatism, the ophthalmologist determines its degree, which is characterized by the length of the distance between the two foci. There are only three degrees of complex farsighted astigmatism:
- Easy degree - up to 2D;
- Average degree - 2-3 D;
- High degree - from 4 D.
In children under the age of 1 year, complex hyperopic astigmatism is considered a physiological norm. Statistics indicate that 25% on Earth have physiological hyperopic astigmatism, in which the difference in the refraction of light rays is 0.5 D. Such a defect does not significantly affect visual acuity and does not provoke other symptoms, so there is no need to correct it.
In children of younger preschool age, complex hyperopic astigmatism of the left eye is most common. In this case, when selecting glasses, an astigmatic glass is inserted into the frame only on the left side, and a simple glass is placed for the right eye. This type of astigmatism in children can be effectively treated with the help of hardware treatment and charging for the eyes.
Visual defects are corrected using special cylindrical glasses. With this diagnosis, the child is placed on dispensary registration, and he is shown to constantly wear glasses.
If all the recommendations of the ophthalmologist are followed, visual acuity can be brought to normal values by the age of 12-13 without the use of corrective surgery. If, for some reason (a high degree of complexity of a refractive anomaly, neglected pathology, etc.), visual disturbances do not lend themselves to spectacle or contact correction, an ophthalmologist may prescribe a surgical correction of the defect.
There are several types of such operations:
- Laser thermokeratoplasty. With this method, the shape of the cornea is changed. Several laser burns are applied to its surface in the periphery by the surgeon, due to which there is an active contraction of collagen fibers, which contributes to a change in the shape of the cornea;
- Thermokeratocoagulation. In fact, the method is similar to the previous one, only here the burns are applied with a thin metal needle, heated to a certain temperature;
- Laser keratomileusis. It is considered the most successful surgical treatment for hypermeptropic astigmatism. With the help of an excimer laser, a kind of "evaporation" of a certain part of the surface layer of the cornea occurs, as a result of which its shape changes.
Mixed
Mixed astigmatism is considered the most severe form of refractive error. With this type of visual impairment, the child is deprived of the opportunity to clearly see objects that are both near and far. The shape of objects is also significantly distorted. Mixed astigmatism is characterized by the presence in the same eye along two main meridians myopia and hyperopia.
This is the main difficulty in the selection of the correction, since the optical power in one meridian must be increased, and in the other - weakened.
The main reason for the formation of mixed astigmatism is a hereditary factor. If a newborn child has a congenital refractive error of this type to a certain extent, then as it grows and approaches one year of age, it will decrease (to about 1 D), which is a physiological norm. This type of astigmatism does not affect visual acuity and does not need any special treatment or the selection of corrective agents. If mixed astigmatism in a child is not diagnosed in time and appropriate treatment is prescribed, then the baby's visual abilities will not develop.
In addition, without proper therapy, after a while, vision will rapidly deteriorate, and as a result, other pathologies of the visual system, such as amblyopia and strabismus, may form.
Therefore, parents need to take special care of the child and, when the first signs of decreased vision appear, contact an ophthalmologist.
Symptoms of mixed astigmatism:
- rapid eye fatigue;
- recurrent headaches (especially in the area of the eyebrows) and dizziness;
- difficulties in recognizing printed text;
- difficulties with prolonged focusing on objects that are at a certain distance (for example, at a blackboard);
- the child, trying to consider any object, tilts his head at different angles and squints his eyes.
The human visual system finishes forming at about 14-16 years old, therefore, if a child is diagnosed with mixed astigmatism, treatment should be started immediately so that the visual skills that he has are not undergone reverse development. Children with this pathology are shown the constant wearing of glasses or contact lenses.
Surgical methods of correcting this refractive anomaly in childhood are rarely resorted to due to the change in the shape of the eyeball as the child grows up.
For information on how to treat astigmatism in children, see the next video.
