With diseases of the organs of vision, patients complain of many factors. Diagnostics includes the following steps, which take into account everything age-related features of the organ of vision:

1. Complaints.
2. Anamnesis
3. External inspection.

External inspection is carried out in good lighting. First, the healthy eye is examined, and then the sick eye. You should pay attention to the following factors:

1. Skin color around the eyes.
2. The size of the palpebral fissure.
3. The condition of the eye membranes is the lapel of the upper or lower eyelid.

The conjunctiva in a normal state is pale pink, smooth, transparent, moist, the vascular pattern is clearly visible.

If there is a pathological process in the eye, an injection is observed:

1. Superficial (conjunctival) - the conjunctiva is bright red, and the cornea turns pale.
2. Deep (pericornial) - around the cornea the color is purple, fades towards the periphery.
3. Examination of the function of the lacrimal gland (lacrimation is not checked in case of complaints).

Functional test. Take a strip of blotting paper 0.5 centimeters wide and 3 centimeters long. One end is bent and inserted into the conjunctival fornix, the other hangs down the cheek. In normal condition, 1.5 cm of strip is wetted in 5 minutes. Less than 1.5 cm is hypofunction, more than 1.5 cm is hyperfunction.

Nasolacrimal tests:

1. Nasolacrimal.
2. Rinsing the nasolacrimal duct.
3. Radiography.

Examination of a sick apple

When examining the eyeball, the size of the eye is assessed. It depends on refraction. With myopia, the eye increases, with farsightedness it decreases.

Protrusion of the eyeball outward is called exophthalmos, retraction is called endophthalmos.

Exophthalmos is a hematoma, orbital emphysema, tumor.

To determine the degree of protrusion of the eyeball, exophthalmometry is used.

Side lighting method

The light source is located to the left and in front of the patient. The doctor sits down opposite. During the procedure, a 20 diopter magnifying glass is used.

Assess: sclera (color, pattern, trabeculae) and pupil area.

Transmitted light research method:

This method evaluates the transparent media of the eye - the cornea, anterior chamber aqueous humor, lens and vitreous body.

The study is carried out in a dark room. The light source is located at the rear left. The doctor is the opposite. Using a mirror ophthalmoscope, a mirror is used to project a light source into the eye. In normal condition, the indicator should light up red.

Ophthalmoscopy:

1. In reverse. The operation is carried out using an ophthalmoscope, a 13 diopter lens and a light source. Holding the ophthalmoscope in the right hand, look with the right eye, the magnifying glass is in the left hand and is placed on the patient’s brow ridge. The result is a mirror inverted image. The retina and optic nerve are examined.
2. Straightforward. A manual electroophthalmoscope is used. The rule of procedure is that the right eye is examined with the right eye, the left eye with the left.

The reverse ophthalmoscope gives a general idea of ​​the condition of the patient's fundus. Directly – helps to detail changes.

The technique is carried out in a certain sequence. Algorithm: optic disc – spot – retinal periphery.

Normally, the optic disc is pink with clear contours. In the center there is a depression from which the vessels emerge.

Biomicroscopy:

Biomicroscopy uses a slit lamp. It is a combination of an intense light source and a binocular microscope. The head is positioned with the forehead and chin resting. Delivers an adjustable light source into the patient's eye,

Gonioscopy:

This is a method of examining the anterior chamber angle. It is carried out using a gonioscope and a slit lamp. This is how the Goldmann goneoscope is used.

A goneoscope is a lens that is a system of mirrors. This method examines the root of the iris and the degree of opening of the anterior chamber angle.

Tonometry:

Palpation. The patient is asked to close the eye and, using the index finger, palpating, judges the amount of eye pressure. Judged by the pliability of the eyeball. Types:

Tn – pressure is normal.

T+ - moderately dense.

T 2+ - very dense.

T 3+ - dense as a stone.

T -1 – softer than normal

T -2 – soft

T-3 – very soft.

Instrumental. During the procedure, a Maklakov tonometer is used - a metal cylinder 4 cm high, weight - 100 g, with extended white glass platforms at the ends.

The weights are treated with alcohol, then wiped dry with a sterile swab. A special paint called collargol is instilled into the eye.

The weight is held on a holder and placed on the cornea. Next, the weight is removed and prints are made on paper moistened with alcohol. The result is assessed using the Polak ruler.

Normal pressure is 18-26 mm Hg.

Development and age-related characteristics of the organ of vision

The organ of vision in phylogenesis has evolved from individual ectodermal-derived light-sensitive cells (in coelenterates) to complex paired eyes in mammals. In vertebrates, the eyes develop in a complex manner: a light-sensitive membrane, the retina, is formed from the lateral outgrowths of the brain. The middle and outer membranes of the eyeball, the vitreous body are formed from the mesoderm (middle germinal layer), the lens - from the ectoderm.

The pigment part (layer) of the retina develops from the thin outer wall of the glass. Visual (photoreceptor, light-sensitive) cells are located in the thicker inner layer of the glass. In fish, the differentiation of visual cells into rod-shaped (rods) and cone-shaped (cones) is weakly expressed, in reptiles there are only cones, in mammals the retina contains predominantly rods; In aquatic and nocturnal animals there are no cones in the retina. As part of the middle (vascular) membrane, already in fish the ciliary body begins to form, which becomes more complex in its development in birds and mammals.

Muscles in the iris and ciliary body first appear in amphibians. The outer shell of the eyeball in lower vertebrates consists mainly of cartilaginous tissue (in fish, amphibians, and most lizards). In mammals it is built only from fibrous tissue.

The lens of fish and amphibians is round. Accommodation is achieved due to movement of the lens and contraction of a special muscle that moves the lens. In reptiles and birds, the lens is capable of not only mixing, but also changing its curvature. In mammals, the lens occupies a constant place; accommodation occurs due to changes in the curvature of the lens. The vitreous body, which initially has a fibrous structure, gradually becomes transparent.

Simultaneously with the complication of the structure of the eyeball, the auxiliary organs of the eye develop. The first to appear are six oculomotor muscles, transformed from the myotomes of three pairs of head somites. The eyelids begin to form in fish in the form of a single ring-shaped fold of skin. Land vertebrates develop upper and lower eyelids, and most of them also have a nictitating membrane (third eyelid) at the medial corner of the eye. In monkeys and humans, the remains of this membrane are preserved in the form of a semilunar fold of the conjunctiva. In terrestrial vertebrates, the lacrimal gland develops and the lacrimal apparatus is formed.

The human eyeball also develops from several sources. The light-sensitive membrane (retina) comes from the lateral wall of the brain bladder (the future diencephalon); the main lens of the eye - the lens - directly from the ectoderm; the vascular and fibrous membranes are from mesenchyme. At an early stage of embryo development (end of the 1st, beginning of the 2nd month of intrauterine life) on the lateral walls of the primary brain bladder ( prosencephalon) a small paired protrusion appears - the eye vesicles. Their terminal sections expand, grow towards the ectoderm, and the legs connecting to the brain narrow and later turn into optic nerves. During development, the wall of the optic vesicle indents into it and the vesicle turns into a two-layer optic cup. The outer wall of the glass subsequently becomes thinner and transforms into the outer pigment part (layer), and from the inner wall a complex light-receiving (nervous) part of the retina (photosensory layer) is formed. At the stage of formation of the optic cup and differentiation of its walls, in the 2nd month of intrauterine development, the ectoderm adjacent to the optic cup in front first thickens, and then a lenticular fossa is formed, which turns into a lenticular vesicle. Having separated from the ectoderm, the vesicle plunges inside the optic cup, loses its cavity, and the lens is subsequently formed from it.

At the 2nd month of intrauterine life, mesenchymal cells penetrate into the optic cup through the gap formed on its lower side. These cells form a blood vascular network inside the glass in the vitreous body that forms here and around the growing lens. The choroid is formed from the mesenchymal cells adjacent to the optic cup, and the fibrous membrane is formed from the outer layers. The anterior part of the fibrous membrane becomes transparent and turns into the cornea. In a 6-8 month old fetus, the blood vessels located in the lens capsule and in the vitreous body disappear; the membrane covering the opening of the pupil (pupillary membrane) dissolves.

The upper and lower eyelids begin to form in the 3rd month of intrauterine life, initially in the form of folds of ectoderm. The epithelium of the conjunctiva, including that covering the front of the cornea, comes from the ectoderm. The lacrimal gland develops from outgrowths of the conjunctival epithelium that appear in the 3rd month of intrauterine life in the lateral part of the developing upper eyelid.

The eyeball of a newborn is relatively large, its anteroposterior size is 17.5 mm, its weight is 2.3 ᴦ. The visual axis of the eyeball is more lateral than in an adult. The eyeball grows faster in the first year of a child’s life than in subsequent years. By the age of 5, the mass of the eyeball increases by 70%, and by 20-25 years - by 3 times compared to a newborn.

The cornea of ​​a newborn is relatively thick, its curvature remains almost unchanged throughout life; The lens is almost round, the radii of its anterior and posterior curvature are approximately equal. The lens grows especially quickly during the 1st year of life; subsequently, its growth rate decreases. The iris is convex anteriorly, there is little pigment in it, the diameter of the pupil is 2.5 mm. As the child gets older, the thickness of the iris increases, the amount of pigment in it increases, and the diameter of the pupil becomes larger. At the age of 40-50 years, the pupil narrows slightly.

The ciliary body in a newborn is poorly developed. The growth and differentiation of the ciliary muscle occurs quite quickly. The optic nerve in a newborn is thin (0.8 mm) and short. By the age of 20, its diameter almost doubles.

The muscles of the eyeball in a newborn are quite well developed, except for their tendon part. For this reason, eye movement is possible immediately after birth, but coordination of these movements begins from the 2nd month of the child’s life.

The lacrimal gland in a newborn is small in size, and the excretory canaliculi of the gland are thin. The function of tear production appears in the 2nd month of a child’s life. The vagina of the eyeball in a newborn and infants is thin, the fatty body of the orbit is poorly developed. In elderly and senile people, the fatty body of the orbit decreases in size, partially atrophies, and the eyeball protrudes less from the orbit.

The palpebral fissure in a newborn is narrow, the medial corner of the eye is rounded. Subsequently, the palpebral fissure rapidly increases. In children under 14-15 years of age, it is wide, which is why the eye appears larger than that of an adult.

The human eyeball develops from several sources. The light-sensitive membrane (retina) comes from the side wall of the brain bladder (the future diencephalon), the lens - from the ectoderm, the choroid and fibrous membrane - from the mesenchyme. At the end of the 1st and beginning of the 2nd month of intrauterine life, a small paired protrusion appears on the lateral walls of the primary brain vesicle - the optic vesicles. During development, the wall of the optic vesicle indents into it and the vesicle turns into a two-layer optic cup. The outer wall of the glass subsequently becomes thinner and transforms into the outer pigment part (layer). From the inner wall of this bubble, a complex light-receiving (nervous) part of the retina (photosensory layer) is formed. At the 2nd month of intrauterine development, the ectoderm adjacent to the optic cup thickens,
then a lens fossa forms in it, turning into a crystal vesicle. Having separated from the ectoderm, the vesicle plunges inside the optic cup, loses its cavity, and the lens is subsequently formed from it.
At the 2nd month of intrauterine life, mesenchymal cells penetrate into the optic cup, from which the blood vascular network and vitreous body are formed inside the optic cup. The mesenchymal cells adjacent to the optic cup form the choroid, and the outer layers form the fibrous membrane. The anterior part of the fibrous membrane becomes transparent and turns into the cornea. In a 6-8 month old fetus, the blood vessels located in the lens capsule and vitreous body disappear; the membrane covering the opening of the pupil (pupillary membrane) dissolves.
The upper and lower eyelids begin to form in the 3rd month of intrauterine life, initially in the form of folds of ectoderm. The epithelium of the conjunctiva, including that covering the front of the cornea, comes from the ectoderm. The lacrimal gland develops from outgrowths of the conjunctival epithelium in the lateral part of the developing upper eyelid.
The eyeball of a newborn is relatively large, its anteroposterior size is 17.5 mm, its weight is 2.3 g. By 5 years, the weight of the eyeball increases by 70%, and by 20-25 years - 3 times compared to a newborn.
The cornea of ​​a newborn is relatively thick, its curvature remains almost unchanged throughout life. The lens is almost round. The lens grows especially quickly during the 1st year of life; subsequently, its growth rate decreases. The iris is convex anteriorly, there is little pigment in it, the pupil diameter is 2.5 mm. As the child gets older, the thickness of the iris increases, the amount of pigment in it increases, and the diameter of the pupil becomes larger. At the age of 40-50 years, the pupil narrows slightly.
The ciliary body in a newborn is poorly developed. The growth and differentiation of the ciliary muscle occurs quite quickly.
The muscles of the eyeball in a newborn are quite well developed, except for their tendon part. Therefore, eye movement is possible immediately after birth, but coordination of these movements begins from the 2nd month of the child’s life.
The lacrimal gland in a newborn is small in size, and the excretory canaliculi of the gland are thin. The function of tear production appears in the 2nd month of a child’s life. The fatty body of the orbit is poorly developed. In elderly and senile people, fat
the body of the orbit decreases in size, partially atrophies, the eyeball protrudes less from the orbit.
The palpebral fissure in a newborn is narrow, the medial corner of the eye is rounded. Subsequently, the palpebral fissure rapidly increases. In children under 14-15 years of age, it is wide, so the eye appears larger than that of an adult.
Anomalies in the development of the eyeball. Complex development of the eyeball leads to birth defects. Most often, there is an irregular curvature of the cornea or lens, as a result of which the image on the retina is distorted (astigmatism). When the proportions of the eyeball are disturbed, congenital myopia (the visual axis is lengthened) or farsightedness (the visual axis is shortened) appears. A gap in the iris (coloboma) most often occurs in its anteromedial segment. Remnants of the branches of the vitreous artery interfere with the passage of light through the vitreous. Sometimes there is a violation of the transparency of the lens (congenital cataract). Underdevelopment of the venous sinus of the sclera (Schlemm's canal) or the spaces of the iridocorneal angle (fountain spaces) causes congenital glaucoma.
Questions for repetition and self-control:

1. List the sense organs, give each of them a functional characteristic.
2. Tell us about the structure of the membranes of the eyeball.
3. Name the structures related to the transparent media of the eye.
4. List the organs that belong to the auxiliary apparatus of the eye. What functions does each of the auxiliary organs of the eye perform?
5. Tell us about the structure and functions of the accommodative apparatus of the eye.
6. Describe the pathway of the visual analyzer from the receptors that perceive light to the cerebral cortex.
7. Talk about the eye's adaptation to light and color vision.

The organ of vision in its development has traveled from individual ectodermal-derived light-sensitive cells (in coelenterates) to complex paired eyes in mammals. In vertebrates, eyes develop in complex ways. A light-sensitive membrane, the retina, is formed from the lateral outgrowths of the brain. The middle and outer membranes of the eyeball, the vitreous body are formed from the mesoderm (middle germinal layer), the lens - from the ectoderm.

The inner shell (retina) is shaped like a double-walled glass. The pigment part (layer) of the retina develops from the thin outer wall of the glass. Visual (photoreceptor, light-sensitive) cells are located in the thicker inner layer of the glass. In fish, the differentiation of visual cells into rod-shaped (rods) and cone-shaped (cones) is weakly expressed, in reptiles there are only cones, in mammals there are predominantly rods in the retina. In aquatic and nocturnal animals there are no cones in the retina. As part of the middle (vascular) membrane, already in fish a ciliary body is formed, which becomes more complex in its development in birds and mammals.

Muscles in the iris and ciliary body first appear in amphibians. The outer shell of the eyeball in lower vertebrates consists mainly of cartilaginous tissue (in fish, partly in amphibians, in most lizards and monotremes). In mammals, the outer shell is constructed only of fibrous tissue. The anterior part of the fibrous membrane (cornea) is transparent. The lens of fish and amphibians is round. Accommodation is achieved due to movement of the lens and contraction of a special muscle that moves the lens. In reptiles and birds, the lens is capable of not only moving, but also changing its curvature. In mammals, the lens occupies a permanent place. Accommodation occurs due to changes in the curvature of the lens. The vitreous body, which initially has a fibrous structure, gradually becomes transparent.

Simultaneously with the complication of the structure of the eyeball, the auxiliary organs of the eye develop. The first to appear are six oculomotor muscles, transformed from the myotomes of three pairs of head somites. The eyelids begin to form in fish in the form of a single ring-shaped fold of skin. In terrestrial vertebrates, upper and lower eyelids are formed. Most animals also have a nictitating membrane (third eyelid) at the medial corner of the eye. The remains of this membrane are preserved in monkeys and humans in the form of the semilunar fold of the conjunctiva. In terrestrial vertebrates, the lacrimal gland develops and the lacrimal apparatus is formed.

The human eyeball also develops from several sources. The light-sensitive membrane (retina) comes from the lateral wall of the brain bladder (the future diencephalon); the main lens of the eye - the lens - is directly from the ectoderm, the vascular and fibrous membranes are from the mesenchyme. At an early stage of embryo development (end of the 1st - beginning of the 2nd month of intrauterine life), a small paired protrusion - the eye vesicles - appears on the lateral walls of the primary brain vesicle. Their terminal sections expand, grow towards the ectoderm, and the legs connecting to the brain narrow and later turn into optic nerves. During development, the wall of the optic vesicle indents into it and the vesicle turns into a two-layer optic cup. The outer wall of the glass subsequently becomes thinner and transforms into the outer pigment part (layer), and the complex light-receiving (nervous) part of the retina (photosensory layer) is formed from the inner wall. At the stage of formation of the optic cup and differentiation of its walls, in the 2nd month of intrauterine development, the ectoderm adjacent to the optic cup in front first thickens, and then a lenticular fossa is formed, turning into a lenticular vesicle. Having separated from the ectoderm, the vesicle plunges inside the optic cup, loses its cavity, and the lens is subsequently formed from it.

At the 2nd month of intrauterine life, mesenchymal cells penetrate into the optic cup through the gap formed on its lower side. These cells form a blood vascular network inside the glass in the vitreous body that forms here and around the growing lens. The mesenchymal cells adjacent to the optic cup form the choroid, and the outer layers form the fibrous membrane. The anterior part of the fibrous membrane becomes transparent and turns into the cornea. In a 6-8 month old fetus, the blood vessels located in the lens capsule and vitreous body disappear; the membrane covering the opening of the pupil (pupillary membrane) dissolves.

Upper And lower eyelids begin to form in the 3rd month of intrauterine life, initially in the form of folds of ectoderm. The epithelium of the conjunctiva, including that covering the front of the cornea, comes from the ectoderm. The lacrimal gland develops from outgrowths of the conjunctival epithelium that appear in the 3rd month of intrauterine life in the lateral part of the developing upper eyelid.

Eyeball in a newborn it is relatively large, its anteroposterior size is 17.5 mm, its weight is 2.3 g. The visual axis of the eyeball runs more laterally than in an adult. The eyeball grows faster in the first year of a child’s life than in subsequent years. By the age of 5, the mass of the eyeball increases by 70%, and by 20-25 years - by 3 times compared to a newborn.

Cornea in a newborn it is relatively thick, its curvature remains almost unchanged throughout life; The lens is almost round, the radii of its anterior and posterior curvature are approximately equal. The lens grows especially quickly during the 1st year of life, and subsequently its growth rate decreases. Iris convex anteriorly, there is little pigment in it, the diameter of the pupil is 2.5 mm. As the child gets older, the thickness of the iris increases, the amount of pigment in it increases, and the diameter of the pupil becomes larger. At the age of 40-50 years, the pupil narrows slightly.

Ciliary body in a newborn it is poorly developed. The growth and differentiation of the ciliary muscle occurs quite quickly. The optic nerve in a newborn is thin (0.8 mm) and short. By the age of 20, its diameter almost doubles.

Muscles of the eyeball in a newborn they are quite well developed, except for their tendon part. Therefore, eye movements are possible immediately after birth, but coordination of these movements is possible only from the 2nd month of life.

Lacrimal gland in a newborn it is small in size, the excretory tubules of the gland are thin. The function of tear production appears in the 2nd month of a child’s life. The vagina of the eyeball in a newborn and infants is thin, the fatty body of the orbit is poorly developed. In elderly and senile people, the fatty body of the orbit decreases in size, partially atrophies, and the eyeball protrudes less from the orbit.

Visual sensory system. The concept of refraction and its change with age. Age-related features of vision: visual reflexes, light sensitivity, visual acuity, accommodation, convergence. Development of color vision in children

Among environmental stimuli, visual ones are especially important for humans. Most information about the outside world is related to vision.

The structure of the eye.

The eye is located in the socket of the skull. Muscles approach the outer surface of the eyeball from the walls of the orbit, and with their help the eye moves.

Eyebrows protect the eyes; they divert sweat flowing from the forehead to the sides. Eyelids and eyelashes protect the eye from dust. The lacrimal gland, located at the outer corner of the eye, secretes a liquid that moisturizes the surface of the eyeball, warms the eye, washes away foreign particles that fall on it, and then flows from the inner corner along the lacrimal canal into the nasal cavity.

The eyeball is covered with a dense tunica albuginea, which protects it from mechanical and chemical damage and the penetration of foreign particles and microorganisms from the outside. This membrane at the front of the eye is transparent. It's called the cornea. The cornea allows light rays to pass through freely.

The middle choroid is penetrated by a dense network of blood vessels that supply the eyeball with blood. On the inner surface of this shell there is a thin layer of a coloring substance - a black pigment that absorbs light rays. The front part of the uvea of ​​the eye is called the iris. Its color (from light blue to dark brown) is determined by the amount and distribution of pigment.

The pupil is the hole in the center of the iris. The pupil regulates the entry of light rays into the eye. In bright light, the pupil reflexively contracts. In low light, the pupil dilates. Behind the pupil is a transparent biconvex lens. It is surrounded by the ciliary muscle. The entire inside of the eyeball is filled with the vitreous humor, a transparent gelatinous substance. The eye transmits rays of light in such a way that the image of objects is recorded on the inner shell - the retina. The retina contains the eye's receptors - rods and cones. Rods are twilight light receptors, cones are stimulated only by bright light, and color vision is associated with it.

In the retina, light is converted into nerve impulses, which are transmitted along the optic nerve to the brain to the visual zone of the cerebral cortex. In this zone, the final differentiation of stimuli occurs - the shape of objects, their color, size, illumination, location and movement.

Refraction of the eye is the refractive power of the optical system of the eye at rest of accommodation. The refractive power of an optical system depends on the radius of curvature of the refractive surfaces (cornea, lens) and on their state from each other. The light refractive apparatus of the eye has a complex structure; it consists of the cornea, chamber humor, lens and vitreous body. On its way to the retina, a ray of light must pass through four refractive surfaces: the anterior and posterior surfaces of the cornea and the anterior and posterior surfaces of the lens. The refractive power of the optical system of the eye is on average 59.92 D. For the refraction of the eye, the length of the axis of the eye is important, that is, the distance from the cornea to the macula. This distance averages 25.3 mm. Therefore, the refraction of the eye depends on the relationship between the refractive power and the length of the axis, which determines the position of the main focus in relation to the retina and characterizes the optical installation of the eye. There are three main refractions of the eye: emmetropia, or “normal” refraction of the eye, farsightedness and myopia. The refraction of the eye changes with age. In newborns, farsightedness is observed predominantly. During the period of human growth, a shift in the refraction of the eye occurs towards its intensification, i.e. myopia. Changes in the refraction of the eye are caused by the growth of the organism, during which the elongation of the eye axis is more pronounced than the change in the refractive power of the optical system. In old age, there is a slight shift in the refraction of the eye towards its weakening due to changes in the lens. The refraction of the eye is determined by subjective and objective methods. The subjective method is based on determining visual acuity using glasses. Objective methods for determining the refraction of the eye are skiascopy and refractometry, i.e., determining the refraction of the eye using special devices - eye refractometers. With these devices, the refraction of the eye is determined by the position of the further point of clear vision.

Convergence of the eyes (from the Latin con I am approaching, converging) is the reduction of the visual axes of the eyes in relation to the center, in which point light stimuli reflected from the object of observation fall on the corresponding places of the retinas in both eyes, due to which the elimination of double vision of the object is achieved.

However, the visual system of a newborn is not similar to the visual system of an adult. The anatomical structure of the organs of vision, which provides visual functions, undergoes significant changes in the process of maturation of the body. The visual system of a newborn is still imperfect, and it will undergo rapid development.

As the baby grows, the eyeball changes very slowly. Its most rapid development occurs in the first year of life. The eyeball of a newborn is 6 mm shorter than the eye of an adult (i.e., it has a shortened anteroposterior axis). This circumstance is the reason that the eye of a recently born child is farsighted, that is, the baby does not see close objects well. Both the optic nerve and the muscles that move the eyeball are not fully formed in a newborn. Such immaturity of the oculomotor muscles forms the physiological, i.e. Strabismus is completely normal for the newborn period.

The size of the cornea also increases very slowly. In newborns, it has a relatively greater thickness than in an adult, is sharply demarcated from the protein membrane and protrudes strongly forward in the form of a roller. The absence of blood vessels in the cornea of ​​the eye explains its transparency. However, in children in the first week of life, the cornea may not be completely transparent due to temporary swelling - this is normal, but if it persists after 7 days of life, then this should be alarming. From the first days of observation, a newborn is attracted by the oval shape and moving objects with shiny spots. This oval corresponds to a human face.

In children and adults up to 25-30 years of age, the lens is elastic and is a transparent mass of semi-liquid consistency, enclosed in a capsule. In newborns, the lens has a number of characteristic features: it is almost round in shape, the radii of curvature of its anterior and posterior surfaces are almost the same. With age, the lens becomes denser, elongates in length and takes on the shape of a lentil grain. It grows especially rapidly during the first year of life (the diameter of the lens of a child’s eye at the age of 0-7 days is 6.0 mm, and at the age of 1 year -7.1 mm).

The iris is shaped like a disk with a hole (pupil) in the center. The function of the iris is to participate in light and dark adaptation of the eye. In bright light the pupil constricts, in low light it dilates. The iris is colored and shows through the cornea. The color of the iris depends on the amount of pigment. When there is a lot of it, the eyes are dark or light brown, and when there is little, they are gray, greenish or blue. The iris in newborns contains little pigment (the eye color is usually blue), is convex and has a funnel shape. With age, the iris becomes thicker, richer in pigment and loses its original funnel-shaped shape.

The rods are responsible for black-and-white or twilight vision, and also help control the peripheral space relative to the point of fixation of the eye. Cones determine color vision and, due to the fact that their maximum number is located in the central part of the retina (yellow spot), where rays focused by all lenses of the eye arrive, they play an exceptional role in the perception of objects located at the point of fixation of the gaze.

Nerve fibers extend from the rods and cones to form the optic nerve, which leaves the eyeball and travels to the brain. The retina of newborns shows signs of incomplete development. The characteristics and development of color vision in children will be discussed below.

The specificity of a newborn's vision is the blink reflex. Its essence lies in the fact that no matter how much you wave objects near the eyes, the baby does not blink, but it reacts to a bright and sudden beam of light. This is explained by the fact that at birth the child’s visual analyzer is still at the very beginning of its development. A newborn's vision is assessed at the level of light sensation. That is, the baby is able to perceive only the light itself without perceiving the structure of the image.

Anatomy of the eye The organ of vision is represented by the eyeball and auxiliary apparatus. The eyeball includes several components: a light-refracting apparatus, represented by a system of lenses: the cornea, lens and vitreous body; accommodative apparatus (iris, ciliary region and ciliary band), which ensures a change in the shape and refractive power of the lens, focusing the image on the retina, and adapting the eye to the intensity of illumination; and a light-perceiving apparatus represented by the retina. The accessory apparatus includes the eyelids, lacrimal apparatus, and extraocular muscles. Development of a baby's vision Very little research has been done into a child's intrauterine vision, but it is known that even a baby born at the 28th week of pregnancy reacts to bright light. A baby born at the 32nd week of pregnancy closes his eyes to the light, and a baby born at term (at 37-40 weeks) turns his eyes, and a little later his head, towards the light source and moving objects. Observation One of the most important achievements of the first two to three months will be the gradual development of the ability to smoothly follow an object moving in different directions and at different speeds.

The process of improving vision begins immediately after birth. During the first year, areas of the cerebral cortex actively develop, in which the centers of vision are located (they are located in the back of the head), receiving information about the outside world. The friendly (simultaneous) movement of the eyes is “honed”, the experience of visual perception is gained, and the “library” of visual images is replenished. A newborn's vision is assessed at the level of light perception. Infants who are a few days old see instead of faces unclear silhouettes and blurred contours with spots where eyes and mouth should be. Subsequently, visual acuity grows, increasing hundreds of times, and by the end of the first year of life it is 1/3-V2 of the adult norm. The fastest development of the visual system occurs in the first months of a baby’s life, while the act of vision itself stimulates its development. Only the eye, onto the retina of which the surrounding world is constantly projected, is capable of developing normally.

First or second weeks of life. Newborns practically do not react to visual stimuli: under the influence of bright light, their pupils narrow, their eyelids close, and their eyes wander aimlessly. However, it has been observed that from the first days a newborn is attracted to oval shapes and moving objects with shiny spots. This is not a rebus at all, it’s just that such an oval corresponds to a human face. The child can follow the movements of such a “face”, and if someone is talking to him, he blinks. But although the child pays attention to a shape similar to a human face, this does not mean that he recognizes any of the people around him. This will take him a lot of time. In the first or second week of life, the baby’s vision is still weakly connected with consciousness. It is known that visual acuity in a newborn is much weaker than in an adult. Such poor vision is explained by the fact that the retina is still developing, and the macula (that part of the retina where 1.0 vision is achieved - i.e. 100%) has not even formed yet. If such vision were observed in an adult, he would experience serious difficulties, but for a newborn, the most important thing is what is large and close: the mother’s face and chest. The baby's field of vision is sharply narrowed, so a person standing to the side of the baby or behind the mother is not perceived by the baby.

Second to fifth weeks of life. The baby can fix his gaze on any light source. Around the fifth week of life, coordinated eye movements in the horizontal direction appear. However, these movements are not yet perfect - lowering and raising the eyes begins later. The baby is only able to fix his gaze on a slowly moving object for a short time and follow its movement. A child's field of vision at the age of about a month is still sharply narrowed; the baby reacts only to those objects that are at a close distance from him and within only 20-30°. In addition, visual acuity remains very weak.

First month. The baby is able to steadily fix his gaze on the eyes of an adult. However, a child's vision up to the fourth month of life is still considered underdeveloped.

Second month. The child begins to master the nearby space. He focuses his eyes on the toys. In this case, vision, hearing and touch are involved, which mutually complement and control each other. The child develops his first ideas about the volume of an object. If colorful toys “float” past him, he will follow them with his eyes in all directions: up, down, left, right. During this period, a preference arises to look at contrasting simple figures (black and white stripes, circles and rings, etc.), moving contrasting objects and generally new objects. The child begins to examine the details of the adult’s face, objects, and patterns.

Thus, one of the most important achievements of the first two to three months will be the gradual development of the ability to smoothly follow an object moving in different directions and at different speeds.

Third or fourth month. The child’s level of development of eye movements is already quite good. However, it is still difficult for him to smoothly and continuously follow an object moving in a circle or making a figure eight in the air. Visual acuity continues to improve.

By three months, babies begin to really enjoy bright colors and moving toys, such as hanging rattles. Such toys perfectly contribute to the development of a child’s vision. From this period, the baby is able to smile when he sees something familiar. He follows an adult's face or an object moving in all directions at a distance of 20 to 80 cm, and also looks at his hand and the object he holds in it.

When a child reaches for an object, he, as a rule, incorrectly estimates the distance to it; in addition, the baby often makes mistakes in determining the volume of objects. He tries to "take" a flower from his mother's dress, not realizing that the flower is part of a flat design. This is explained by the fact that until the end of the fourth month of life, the world reflected on the retina still remains two-dimensional. When your baby opens the third dimension and can estimate the distance to his favorite rattle, he will learn to make targeted grasping. By analyzing the slightest discrepancies between the visual images of both eyes, the brain gets an idea of ​​​​the depth of space. In newborns, signals enter the brain in a mixed form. But gradually the nerve cells that perceive the picture are demarcated, and the signals become clear. Children's perception of volume develops when they begin to move in space.

At the age of four months, the child is able to predict events that are about to happen. Just a few weeks ago he kept screaming from hunger until the nipple came into his mouth. Now, when he sees his mother, he immediately reacts in one way or another. He can either become silent or start screaming even louder. Obviously, a connection is established in the child’s mind based on a certain stereotype. Thus, one can notice the establishment of a connection between visual abilities and consciousness. Along with the fact that the child begins to understand the functions of surrounding objects (what these objects are intended for), he acquires the ability to react to their disappearance. The baby will follow the moving rattle and look closely at the place where he last saw it. The child tries to restore in his memory the trajectory of the rattle's movement.

Somewhere between three and six months of a child's life, the retina of his eyes develops enough that he can distinguish small details of objects. The baby is already able to move his gaze from a close object to a distant one and back, without losing sight of it. From this period, the baby develops the following reactions: blinking when an object quickly approaches, examining himself in the reflection of the mirror, recognizing the breast.

Sixth month. The child actively examines and examines his immediate environment. He may get scared when he finds himself in a new place. Now the visual images that he encounters are especially important for the child. Previously, the baby, playing with his favorite toy, hit the object in search of interesting sensations, then grabbed it to put it in his mouth. A six-month-old baby is already picking up objects to examine them. Grasping becomes more and more precise. Based on this, a visual idea of ​​distance is formed, which, in turn, develops three-dimensional perception in the baby. The child is able to choose his favorite toy with his eyes. He already manages to focus his eyes on an object located at a distance of 7-8 cm from his nose.

Seventh month. One of the most characteristic features of a child during this period is the ability to notice the smallest details of the environment. The baby immediately discovers the pattern on the new sheet. In addition, he begins to be interested in the interrelationship of surrounding objects.

Eighth to twelfth months. During this period, the child perceives the object not only as a whole, but also in its parts. He actively begins to look for objects that suddenly disappear from his field of vision, because... understands that the object has not ceased to exist, but is located in another place. The baby's facial expression changes depending on the adult's facial expression. He is able to distinguish “friends” from “strangers”. Visual acuity further increases.

From one year to 2 years. Almost complete coordination of eye and hand movements is achieved. A child watches an adult write or draw with a pencil. He is able to understand 2-3 gestures (“bye”, “no”, etc.).

At the age of 3-4 years, a child’s vision becomes almost the same as that of an adult.