First, let’s try to deal with the first question: what is visual acuity? So called the ability to distinguish small parts of objects. Moreover, the smaller they are, the higher the visual acuity of a person.
It is customarily measured in decimal fractions: 0.1; 0.2; 0.3. 1.0; 1.1; 1.2, etc. The development of visual acuity in very young occurs gradually.
Immediately after birth, the child sees very little: while he only reacts to the light (turning his head towards him for a while), and also tries to follow large moving objects. However, very soon the picture will change most drastically: in 2-5 weeks the baby will look confidently at the light, by the end of the 2nd month – look at large objects, at three months – revive, noticing a mother’s breast or a bottle, at four – grabbing objects proportional to the palm of your hand.
How to understand that the sight of the baby is all right? To do this, you can use several methods.
Ensure that the baby is sitting at the table properly (the distance from the eyes to the working surface should be 30–33 cm), take care of good lighting, exercise prudence and limit the time the child spends watching TV and / or computer (in total to hours a day). Particular attention is paid to a small mobile lifestyle, write it in the sports section for regular activities.
On the background of the window, hang a bright red ball with a diameter of 4 cm and slightly swing it. Take the baby in your arms, begin to approach the object and note the distance from which the child will react to his “appearance”.
Then do the counting: if the kid sees the ball from 1 m, his visual acuity will be 0.03; from 3 m – 0.11, from 5 m – 0.18 (conditional rate for 6-month-old children – 0.1–0.3).
After the child is half a year old, a ball with a diameter of 0.7 cm will be needed for the study. If the baby sees the object from a distance of 1 m, his visual acuity will be 0.2, with 3 m – 0.6, with 5 m – 1.0 (the norm for one-year-old children is 0.3–0.6).
To understand how a child sees in 1-2 years, you can use another technique. In a bright room with a length of at least 5 m, apply marks to the floor at intervals of 1 m. At a distance of 5 m, place a white ball 4 cm in diameter.
If you succeed, put a blindfold on one eye on the child, enter the room with him, show the same ball, ask him to look for his double and bring it. If the child cannot complete the assignment, move the ball to the 4, 3 or 2 m mark, that is, bring the object closer until it is detected.
If the kid sees a ball with a diameter of 4 cm by 5 m, take a ball with a diameter of 0.7 cm and repeat the study.
ATTENTION! Remember that the second technique will require considerable effort from you.
Fortunately, in most cases it is not necessary to resort to it: to understand how a baby’s vision develops is quite simple. be attentive to parents. Observe whether a child distinguishes small parts of toys, collects crumbs and mote from the floor, sees moving machines and human figures in the window, how he reacts to objects located at different distances from him, and tell the doctor about it.
To avoid eye problems, it is important to regularly visit an ophthalmologist. Of great importance are routine medical examinations, which are carried out in the first weeks after birth, in one and three years, and also in front of the school.
Check the visual acuity of the child in a more familiar way, that is, according to special tests, usually possible with 3 years. Most often, this is done using the Orlova table, which contains 10 rows of silhouette images. The baby is seated at a distance of 5 m and in each row, starting from the top, one picture is shown.
If a small one cannot name it, move to another, located on the same line, and so on. The purpose of the study is to wait until a larger number of pictures in the same row are correctly named. This line will determine the visual acuity of the baby.
Usually at 3 years it is 0.6–0.9, at 4 years – 0.7–1.0, at 5 years – 0.8–1.0, at 6 years – 0.9–1.0 and above. Thus, visual acuity increases from birth to school and reaches the norm of an adult by 7–8 years.
When do preschool children get glasses? Before answering this question, you need to talk about what a refraction is.
We give this phenomenon a medical definition: this is the name given to the total refractive power of the optical media of the eye, that is, the cornea and lens. It is measured in diopters. Refraction can be commensurate when the focus of the image coincides with the retina, and disproportionate when they do not coincide.
In cases where the focus is behind the retina, refraction is considered to be far-sighted, in front of the retina it is considered nearsighted. Normally, children from birth to seven years have some farsightedness: a month-old child has up to 4 diopters, a seven-year-old has up to 1 diopter.
Remember that in the first weeks after the birth of a child, the movements of his eyes are chaotic and uncoordinated; in addition, they can periodically be deflected, which is due to the immaturity of the visual system. Usually after four months, the eyes are in the correct position. Another thing, if the newborn has a sharp and constant deviation of the eye.
This is a congenital strabismus, and it requires the close attention of a specialist.
When does a child get glasses?
A child with long-sightedness will need glasses in the case of converging strabismus or a steady reduction in visual acuity – scientifically, amblyopia, and simply – a “lazy eye”.
Children with small myopia (1–2 diopters) are recommended rarely to recommend them; more often, up to seven years they are not prescribed at all. In the case of severe myopia, glasses are prescribed and very small.
Another state of refraction that requires wearing glasses is astigmatism (this is the name of one of the anomalies of the eye’s optics, due to which the organ of vision has to do additional work). If at the same time visual acuity is reduced, the child will need to constantly wear specially selected glasses with cylindrical lenses.
Since you need to take care of eye health literally from the cradle, the first visit to an ophthalmologist is prescribed in the first months after the birth of the child. The next expert consultation (if there are no problems) will be needed in 1–1.5 and 3 years, and then before the school. What does eye examination include?
First of all, the doctor assesses the position and mobility of the eyes, the state of the optical media (the cornea and lens), the fundus and the refraction.
The human eye is an almost regular sphere with a diameter of about 24 mm. It consists of three shells: outer (fibrous), medium (vascular) and inner (retina).
The transparent structures of the eye include the lens, vitreous and intraocular fluid. The fibrous membrane consists of an opaque part of white color – the sclera and the cornea – the anterior, transparent part of the outer shell of the eye.
The iris, located behind the cornea, is a membrane with a hole in the center – the pupil. In bright light, the pupil narrows, and in the dark it expands to allow more light to reach the retina.
Behind the iris there is an elastic dense formation – the lens. It is transparent, has the shape of a biconvex lens and, together with the cornea, constitutes the optical system of the eye. The retina lining the fundus of the eye and is part of the central nervous system.
Through the cornea and lens, the rays from the objects in question arrive at the retina and form an image on it, which is then converted into nerve impulses.
What is strabismus? So called the deviation of one of the eyes from the joint point of fixation. In addition to the very psychologically unpleasant cosmetic defect, strabismus is the cause of serious violations.
First of all, we are talking about the disorder of binocular vision – the ability to merge images obtained on the retina of two eyes into a single visual image. In addition, the child’s visual acuity decreases.
Squint occurs in 2-3% of babies and occurs, as a rule, between the ages of 1 and 3 years. Often anxious mothers at the doctor’s office say that the deviation of the eye was due to the fact that the child was frightened, fell and hurt his head or after an illness with a high fever.
However, it should be understood that all this does not apply to the real causes of the disease – most children fall and are ill, but strabismus does not develop in them. Most likely, the circumstances described above simply serve as a trigger for the appearance of deviations.
What can lead to strabismus?
- Noticeable reduction in the vision of one of the eyes. It can be associated with some diseases or injuries, which is why a worse seeing eye cannot work actively and deviates to one side or the other.
- The difference in the refractive power of two eyes, when images of different size are formed on the fundus. In some circumstances, the ability to merge visual images into a single whole is lost, and the eye that is in worse conditions begins to mow.
- Strabismus can result from enhanced (due to farsightedness) or weakened (due to short-sightedness) accommodation – this is the name for adapting the eye to a clear vision of objects that are at a distance from it. In the first case, convergent strabismus develops, in the second – divergent.
- Problems with the central nervous system – inflammation, trauma, tumors can lead to strabismus.
If you notice one or more of the following symptoms: wandering eyes, involuntary eye movements (scientifically nystagmus), photophobia, corneal edema or opacification, white-gray, and not black pupil, consult your doctor immediately!
To diagnose, the doctor examines the anterior part of the eye, the light refracting the medium and the fundus of the eye. In addition, the doctor examines visual acuity, refracting ability (myopia, hyperopia or astigmatism), binocular vision, eye mobility, and the angle of strabismus. After that, the ophthalmologist develops a whole strategy of action, the ultimate goal of which is to restore binocular vision.
Usually, treatment includes several stages: pleoptic, orthotics, pre- and postoperative exercises, surgical operation according to indications and diploptic. Let’s talk about this in more detail.
– Pleoptico is the treatment of amblyopia – reducing visual acuity. She begins with the discharge points, as a rule, for constant wear.
They are needed in order to form clear images on the retina of the sore eye and it can work more actively. In addition, sometimes glasses restore the symmetrical position of the eyes and help them start working together.
In addition, the pleoptic includes direct occlusion (gluing better than the seeing eye), various types of light (the “lazy eye” looks at a bright light), classes on special equipment with various visual loads and medical and educational exercises. We are talking about classes with mosaics, beads, modeling and weaving paper mats (the size of the details of the games are selected according to the degree of reduction of vision).
In addition, recently there have been new directions in the treatment of amblyopia: laser, reflexotherapy, electrical stimulation, computer treatment, biofeedback methods, and so on.
– If after the measures have been taken, the vision has improved, and the eyes began to be fixed correctly, the doctor proceeds to the next stage – orthoptics, that is, to develop the ability to combine two images into a single visual image in certain conditions. If the problem cannot be solved with the help of orthoptics, an operation is assigned. Her goal – to achieve the correct position of the eyes.
The optimal time for surgery is 4–5 years.
In order for the child to understand what will be required of him at the time of testing – eye tests, show him the table in advance and ask him to name what is shown on it.
– The final stage of treatment – diploptica – development of binocular vision under natural conditions: the patient “works” with one object common to both eyes, as is the case in real life. Assign diploptic in the event that the position of the eye became symmetrical or close to it.
Remember that strabismus treatment can last for several years. In preschool children, it is conducted in specialized kindergartens, where the stay of children is organized according to the principle “playing, we are treated.”
In addition, children can receive assistance in inter-district eye protection cabinets.
There is also a number of eye resorts. As for operations, they are made in eye clinics. After entering the school, the child can continue treatment in the eye care office.
However, the maximum effort to get rid of strabismus must still focus on the preschool age.
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