The organ of vision is one of the most important human organs, because it is thanks to the eyes that we receive about 85% of information from the outside world. A person does not see with his eyes, they only read visual information and transmit it to the brain, and there a picture of what he saw is already formed. The eyes are like a visual intermediary between the outside world and the human brain.
The eyes are very vulnerable, the anatomy of the structure of the eyeball suggests many different diseases that can be prevented, you just need to go a little deeper into knowledge of anatomy.
Definition
The eye is a paired organ of the human visual system, which is susceptible to magnetic radiation in terms of light provides the function of vision.
based on the anatomy of the human eyeball, it is located in the upper part of the face with components: eyelids, eyelashes, lacrimal system. The eyes are actively involved in human facial expressions.
Details of the anatomyeyeball, each of its components.
Eyelids
Under the eyelids, we mean the skin folds above the eyeball, which are always mobile, due to this, the blinking of the eyes occurs. This is possible due to the ligaments that are located along the edges of the eyelids. The eyelids have 2 ribs: anterior and posterior, with an intermarginal area between them. This is where the ducts of the meibomian glands come in. According to the anatomy of the eyeball, these glands produce a secret that lubricates the eyelids so they can glide.
There are hair follicles on the front edge of the eyelid, they provide eyelash growth. The posterior rib functions so that both eyelids fit snugly around the eyeball.
The eyelids are responsible for saturating the eye with blood and conduct nerve impulses, and also have the function of protecting the eyeball from mechanical damage and other influences.
Eye socket
The eye socket is called the bony cavity that protects the eyeball. Its structure includes four parts: outer, inner, upper and lower. All these parts are securely interconnected and form a solid whole. The outer part is the strongest, the inner part is somewhat weaker.
The bone cavity is adjacent to the air sinuses: inside - with the ethmoid labyrinth, above - with the frontal emptiness, below - with the maxillary sinus. Such a neighborhood is somewhat dangerous due to the fact that with tumor formations in the sinuses, they can develop in the orbit itself. The opposite is also possible: the eye socket is connected to the skull, so there is a possibility of the inflammatory process moving intoparts of the brain.
Pupil
The pupil of the eyeball is a part of the structure of the organ of vision, a recessed round hole, which is located in the very center of the iris of the eyeball. Its diameter is variable, this regulates the penetration of light particles into the inner part of the eye. The anatomy of the muscles of the eyeball is represented by the following muscles of the pupil: sphincter and dilator. The sphincters are responsible for ensuring the constriction of the pupil, the dilator - for its expansion.
The size of the pupils is self-regulating, a person cannot influence this process in any way. But it is influenced by an external factor - the level of illumination.
The pupillary reflex is provided through sensitivity and elevation of motor activity. First, there is a signal in response to some impact, then the work of the nervous system begins, which provokes a reaction to a specific stimulus.
Lighting contributes to the constriction of the pupil, this separates the blinding light, which preserves vision throughout a person's life. This reaction is characterized in two ways:
- direct reaction: one eye is exposed to light, it reacts properly;
- friendly reaction: the second eye is not illuminated, but reacts to light that affects the first eye.
Optic nerve
The function of the optic nerve is the delivery of information to a part of the brain. The optic nerve follows the eyeball. The length of the optic nerve is no more than 5-6 cm. The nerve is immersed in a fatty space, which protects it from damage. The nerve originates in the back of the eyeball, it is there that the cluster of nerve processes is located, they give shape to the disk, which, going beyond the orbit, descends into the membranes of the brain.
The processing of information received from the outside depends on the optic nerve, it is it that delivers information regarding the received visual picture to certain areas of the brain.
Cameras
In the structure of the eyeball there are closed spaces, they are called the chambers of the eyeball, they contain intraocular fluid. There are only two such cameras: front and back, they are interconnected, and the connecting element for them is the pupil.
The anterior chamber is the area behind the cornea, the posterior chamber is behind the iris. The volume of the chambers is constant, it does not change under the influence of external factors. The functions of the cameras are in the relationship between different intraocular tissues, in the receipt of light signals on the retina.
Schlemm's channel
This is a passage inside the sclera, named after the German doctor Friedrich Schlemm. In the anatomy of the eyeball, it occupies an important place.
This channel is necessary in order to remove moisture and ensure its absorption by the ciliary vein. The structure resembles a lymphatic vessel. With infectious processes in the Schlemm's canal, a disease occurs - glaucoma of the eye.
Sheaths of the eye
Fibrous membrane of the eye
This is a connective tissue that maintains the physiological shape of the eye, is also protectivebarrier. The structure of the fibrous membrane suggests the presence of two components: the cornea and the sclera.
- Cornea. Transparent and flexible shell, the shape resembles a convex-concave lens. Functionality is similar to a camera lens - focusing light rays. Includes five layers: endothelium, stroma, epithelium, Descemet's membrane, Bowman's membrane.
- Sclera. Opaque shell of the eyeball, which ensures the quality of vision due to the fact that it prevents the penetration of light rays through the sclera membrane. The sclera serves as the basis for the elements of the eye that are outside the eyeball (vessels, muscles, ligaments and nerves).
Choroid of the eye
The anatomy of the structure of the eyeball involves the layering of the choroid, it consists of three parts:
- Iris. The shape is a disc, in the center of which is the pupil. Includes three layers: pigment-muscular, borderline and stromal. The boundary layer is made up of fibroblasts, followed by melanocytes containing color pigment. The color of the eyes depends on the number of melanocytes. Next is the capillary network. The back of the iris is made up of muscles.
- Ciliary body. In this part of the vascular membrane of the eye, the production of eye fluid occurs. The ciliary body consists of muscles and blood vessels. The activity of the layers of the ciliary body makes the lens work, as a result we get a clear image, being at different distances from the object in question. Also this partchoroid keeps heat in the eyeball.
- Chorioidea. The vascular part, which is located behind, is located between the dentate line and the optic nerve, consists mainly of the ciliary arteries of the eye.
Retina
The structure of the eyeball that regulates the amount of light is called the retina. This is the peripheral part of the eyeball, which is involved in starting the work of the visual analyzer. With the help of the retina, the eye picks up waves of light, converts them into impulses, and then they are transmitted to the brain through the optic nerve.
The retina is also called the retina, it is the nerve tissue that forms the eyeball in the element of its inner shell. The retina is the limiting space in which the vitreous body is located. The structure of the retina is complex and multi-layered, each layer is in close interaction with each other, damage to any of the layers of the retina has negative consequences. Consider each of the layers:
- The pigment epithelium is a barrier to light emission so that the eye is not blinded. Functions are wide - protection, nutrition of cells, transport of nutrients.
- Photosensory layer - contains cells highly sensitive to light in the form of cones and rods. The rods are responsible for the sensation of color, and the cones are responsible for seeing in low light.
- Outer membrane - collects light rays on the retina and delivers them to the receptors.
- Nuclear layer - consists of cell bodies and nuclei.
- Plexiform layer - characterized by cell contacts that occur between cell neurons.
- Nuclear layer - thanks to tissue cells, it supports important nerve functions of the retina.
- Plexiform layer - consists of plexuses of nerve cells in their processes, separates the vascular and avascular parts of the retina.
- Ganglion cells - are conductors between the optic nerve and light-sensitive cells.
- Ganglion cell - forms the optic nerve.
- Boundary membrane - consists of Muller cells and covers the inside of the retina.
Vitreous body
In the photo of the eyeball, you can see that the structure of the vitreous body resembles a gel-like substance, fills the eyeball by 70%. Consists of 98% water, also contains a small amount of hyaluronic acid.
In the anterior zone there is a recess adjacent to the lens of the eye. The posterior zone is in contact with the membrane sheath of the retina.
Main functions of the vitreous body:
- gives the eye a physiological shape;
- refracts rays of light;
- creates the necessary tension in the tissues of the eyeball;
- helps achieve incompressibility of the eyeball.
Crystal
This is a biological lens, it is biconvex in shape, performing the function of conducting and refracting light. Thanks to the lens, the eye can focus on different objects at different distances.
The lens is located in the posterior chamber of the eyeball, height from 7 to 9mm, thickness about 5 mm. With age-related changes in the eye, the lens becomes thicker.
Inside the lens there is a substance that holds a special capsule with the thinnest walls, consisting of epithelial cells. Epithelial cells are constantly dividing.
Functions of the lens of the eyeball:
- Light transmission - the lens is transparent, so it easily conducts light.
- Refraction of light rays - the lens is a human biological lens.
- Accommodation - the shape of a transparent body can change in order to clearly see objects at different distances.
- Separation - participates in the formation of two bodies of the eye: anterior and posterior, this allows you to keep the vitreous in its place.
- Protection - The lens protects the eye from the penetration of pathogens, once they are in the anterior chamber of the eye, they cannot pass further.
Zinn Bundle
The ligament is formed from fibers that fix the lens in place, it is located just behind it. The ligament of Zinn helps the ciliary muscle to contract, which changes the curvature of the lens, and the eye focuses on objects located at different distances.
Zinn's ligament is the main element of the eye system, which provides its accommodation.
Functions of the eyeball
Light perception
This is the ability of the eye to distinguish light from darkness. There are 3 functions of light perception here:
- Daytime vision: Provided by cones, suggests good visual acuity, wide palettecolor perception, increased contrast of vision.
- Twilight vision: in low light, the activity of the rods can improve the quality of vision. It is characterized by high-quality peripheral vision, achromaticity, dark adaptations of the eye.
- Night vision: occurs due to rods under certain limits of illumination, is reduced only to the sensations of light waves.
Central (subject) vision
The ability of the eyeball to distinguish objects by their shape and brightness, as well as to recognize the details of objects. Central vision is provided by cones, measured by visual acuity.
Peripheral vision
Helps to navigate and move in space, provides twilight vision. Measured by the field of view - during the study, the boundaries of the field are found and defects of vision inside these boundaries are detected, red, white and green colors are used for the study.
Color sensation
Characterized by the ability of the eye to distinguish colors from each other. Irritants: green, blue, purple and red. Color perception is due to the activity of cones. The study of color perception is carried out using spectral and polychromatic tables.
Binocular vision is theprocess of seeing with two eyes.
Common eye diseases
- Angiopathy. A disease of the vessels of the retina of the eyeball, which occurs when the blood circulation of the vessels is disturbed. Symptoms may include: blurred vision, lightning ineyes. Most often this disease occurs in people over 35 years of age. After examining the fundus, the doctor makes a diagnosis.
- Astigmatism. This is an anomaly in the structure of the optical system of the eyeball, in which the rays of light are subjected to incorrect focusing on the retina. The work of the lens or cornea may be disrupted, depending on this, corneal or lens astigmatism is isolated. Symptoms include blurred vision, double vision, blurry objects.
- Myopia. Such a violation of the function of the eyeball is explained by the fact that the optical eye system is distorted when the focus of the subject of the image is concentrated not on the retina, but on its front region. Because of this, a person sees distant objects blurry and indistinct, this does not apply to nearby objects. The degree of pathology is determined by the clarity of distant images.
- Glaucoma. An anomaly that is a chronic disease, glaucoma leads to irreversible changes in the optic nerve due to a periodic or constant increase in intraocular pressure. It occurs either without symptoms or with minor visual impairment. If a person does not receive proper treatment for glaucoma, it will eventually lead to blindness.
- Hyperopia. Pathology of the eyeball, characterized by the focusing of the image behind the retina. With minor deviations, vision remains normal, with moderate changes, focusing of vision is difficult on close objects, with severe pathology, a person sees poorly both close and far. farsightednessaccompanied by headaches, strabismus and visual fatigue.
- Diplopia. Dysfunction of the visual apparatus, in which the image is seen with doubling due to the fact that the eyeball is deviated from its normal position. This pathology of vision occurs due to damage to the muscle fibers of the eyeball. Doubling variations can be as follows: a person sees a parallel doubling of the image; a person sees the doubling of the image on top of each other. With diplopia, patients complain of frequent aching headaches.
- Cataract. It occurs due to the fact that in the lens there is a slow process of replacing water-soluble proteins with water-insoluble ones, this is accompanied by swelling and inflammation of the lens, and the transparent body also begins to become cloudy. The anomaly is dangerous because the process is irreversible, and the course of the disease passes rapidly and quickly.
- Cyst. This benign neoplasm can be congenital or acquired. At the beginning of the disease, small blisters form with inflamed skin around them, then they grow rapidly and require medical intervention. The process is accompanied by a weakening of vision, pain when blinking the eyelids. The reasons can be different: from heredity to acquired inflammation.
- Conjunctivitis. This is an inflammation in the conjunctiva of the eye - the transparent membrane of the eyeball. May be viral, allergic, fungal or bacterial. Some types of conjunctivitis are highly contagious and can be transmitted through household hygiene products, and can also be transmitted from animals. Symptoms of the disease - purulentdischarge from the eyes, swelling of the eyeball, hyperemia, burning and itching of the eyelids.
- Retinal detachment. This pathology is characterized by the separation of the layers of the retina of the eyeball from the pigment epithelium and choroid. An extremely dangerous disease, in the presence of which one cannot do without surgical medical intervention. Otherwise, there is a risk of complete loss of vision, since the process is irreversible. With retinal detachment, the patient has vision problems, sparks and a veil in front of the eyes, the shape and size of the objects in question are distorted.
Treatment of eye diseases
After a diagnostic examination by an ophthalmologist and a diagnosis, treatment is prescribed. Depending on the cause of the disease, the doctor selects the desired method, the group of which part of the eye the disease belongs to is of great importance.
When the eyeball is affected by an infection or fungus, antibiotic-based drugs are usually prescribed, these can be eye drops, tablets, ointments that are placed under the lower eyelid, as well as intramuscular injections. Such funds kill germs and prevent further development of the disease.
If visual dysfunction is associated with functional damage to the eyeball, then glasses are prescribed as a treatment, for example, this is widely practiced for astigmatism, myopia, hyperopia.
When visual impairment is accompanied by pain in the eyes and headaches, then ophthalmic surgery may be prescribed.surgeon, for example, with glaucoma of the eye. Currently, for eye surgery, the laser method is increasingly being used, it is the least painful and very fast. Such an operation allows you to solve the problem of eye disease in just a few minutes, there are practically no complications. Used for myopia, astigmatism and cataracts.
With eye strain and occasional pain, supportive methods can be used: take vitamin complexes to improve vision, eat foods that improve the quality of vision (blueberries, seafood, carrots and others).
We looked at the anatomy of the human eyeball. Proper nutrition, a clear daily routine, 8-hour sleep - all this can be an excellent prevention of eye diseases. Eating fresh fruit, being active and limiting your time at computers play a big role in quality vision for years to come!
