Anatomy of the lens. Lens of the eye - shape and structure (size, curvature, optical power, layers and proteins)

The lens, together with the cornea, aqueous humor and vitreous body, constitutes the optical (refractive) system of the eye and is a biological lens in this system.

In the eye, the lens is located immediately behind the iris in a depression (fossa patellaris) on the front surface vitreous. In this position, it is held by numerous fibers, which together form a suspensory ligament - the ciliary girdle. These fibers extend towards the equator of the lens from the flat part of the ciliary body and its processes. Partially crossing, they are woven into the lens capsule 2 mm anteriorly and 1 mm posteriorly from the equator, forming the Petite canal and the zonular plate.

The posterior surface of the lens, like the anterior one, is washed by aqueous humor, since it is separated from the vitreous body almost along its entire length by a narrow gap (retrolental space).

Along the outer edge, this space is limited by the annular ligament of Wieger, which fixes the lens to the vitreous body. Therefore, the surgeon must remember that careless traction during cataract extraction can cause damage to the anterior hyaloid membrane of the vitreous and even retinal detachment.

Damage to the lens is observed both during contusion of the eye, its penetrating injury, and during intraocular surgical interventions(more often during antiglaucomatous surgery). Maintaining the transparency of the lens is possible only with minor point destruction of the capsule. In such cases, the resulting defect is closed by epithelial cells and no further destructive changes in the fibers are observed. With more extensive damage, cataracts develop.

Since the capsule did not recover is infused, an irreversible disruption of the relationship between the fibers and the moisture of the anterior chamber occurs. The reason for this is swelling of the fibers, their destruction and, naturally, a violation of transparency. The process is progressing steadily. The degeneration of the lens epithelium intensifies and the zone of fiber destruction expands. In some cases, reactive proliferation of epithelial cells is observed, leading to the formation of so-called secondary cataracts.

Structure

The lens has the form of a transparent elastic biconvex lens, circularly fixed to the ciliary body, with a diameter of 9-10 mm, the maximum thickness of the lens of an adult is approximately 3.6-5 mm (depending on the tension of accommodation), with its anterior, less convex surface adjacent to the iris, the posterior one, more convex, - to the vitreous body. The central points of the front and rear surfaces are called the anterior and posterior poles, respectively. The peripheral edge where both surfaces meet each other is called the equator. Both poles are connected by the axis of the lens.

Dimensions and optical properties

The radius of curvature of the anterior surface of the lens at rest of accommodation is 10 mm, and the posterior surface is 6 mm; at maximum accommodation stress, the anterior and posterior radii are compared, decreasing to 5.33 mm. The refractive index of the lens is not uniform in thickness and averages 1.414 or 1.424, also depending on the state of accommodation. At rest of accommodation, the refractive power of the lens averages 19.11 diopters, at maximum accommodation voltage - 33.06 diopters.

In newborns, the lens is almost spherical, has a soft consistency and a refractive power of up to 35.0 diopters. Its further growth occurs mainly due to an increase in diameter.

The lens is enclosed in a thin capsule, the anterior part of which is lined with single-layer cuboidal epithelium. The posterior part of the capsule is thinner than the anterior one.

The lens is held in its position by the zonular ligament, which consists of many smooth and durable muscle fibers, going from the lens capsule to the ciliary body, where these fibers lie between the ciliary processes. Between the fibers of the ligament there are fluid-filled spaces that communicate with the chambers of the eye. The substance of the lens consists of a denser core located in the central part, which, without a sharp boundary, continues into the softer part - the cortex.

Lens composition:

• water - 65%,
• proteins - 30%,
• inorganic compounds (potassium, calcium, phosphorus),
• vitamins,
• enzymes,
• lipids.

The lens of young people contains mostly soluble proteins, in the redox processes of which cysteine ​​is involved. Insoluble proteins - albuminoids do not contain cysteine; they contain insoluble amino acids (leucine, glycine, tyrosine and cystine).

Histological structure

• Capsule

On the outside, the lens is covered with a thin elastic structureless capsule, which is a homogeneous transparent shell that strongly refracts light and protects the lens from the effects of various pathological factors. The capsule is attached to the ciliary body using the ciliary girdle.

The thickness of the lens capsule is not the same over its entire surface: the front part of the capsule is thicker than the back (0.008-0.02 and 0.002-0.004 mm, respectively), this is due to the fact that on the front surface under the capsule there is a single layer of epithelial cells.

The capsule reaches its greatest thickness in two of its belts concentric to the equator - the anterior (located 1 mm inward from the place of attachment of the anterior fibers of the ciliary girdle) and the posterior (inward from the place of posterior attachment of the ciliary girdle). The thinnest capsule is in the region of the posterior pole of the lens.

• Epithelium

The lens epithelium is a layer of cubic cells; its main functions are trophic, cambial and barrier.

The epithelial cells corresponding to the central zone of the capsule (opposite the pupil) are flattened and tightly adjacent to each other. Almost no cell division occurs here.

As we move from the center to the periphery, there is a decrease in the size of epithelial cells, an increase in their mitotic activity, as well as a relative increase in the height of the cells so that in the equator region the lens epithelium practically turns into prismatic, forming the growth zone of the lens. Here the formation of so-called lens fibers occurs.

• Lens substance

The bulk of the lens is formed by fibers, which are elongated epithelial cells. Each fiber is a transparent hexagonal prism. The substance of the lens, formed by the protein crystallin, is completely transparent and, like other components of the light-refracting apparatus, is devoid of blood vessels and nerves. The central, denser part of the lens has lost its core, shortened, and when superimposed on another fiber it began to be called core, while the peripheral part forms a less dense bark.

During intrauterine development, the lens receives nutrition from the vitreous artery. In adulthood, the nutrition of the lens is entirely dependent on the vitreous body and aqueous humor.

Functions

1. Light transmission: The transparency of the lens allows light to pass to the retina.
2. Refraction: Being a biological lens, the lens is the second (after the cornea) light-refracting medium of the eye (at rest the refractive power is about 19 diopters).
3. Accommodation: The ability to change its shape allows the lens to change its refractive power (from 19 to 33 diopters), which ensures focusing vision at different angles. distant objects. When fibers contract ciliary muscle, innervated by the oculomotor and sympathetic nerves, relaxation of the zonular fibers occurs. At the same time, the tension of the lens capsule decreases and, due to its elastic properties, it becomes more convex, creating conditions for viewing close objects. Relaxation of the ciliary muscle leads to flattening of the lens, creating the eye's ability to see well into the distance.
4. Dividing: Due to the peculiarities of the location of the lens, it divides the eye into the anterior and posterior sections, acting as an “anatomical barrier” of the eye, keeping the structures from moving (does not allow the vitreous body to move into the anterior chamber of the eye).
5. Protective function: the presence of a lens makes it difficult for microorganisms to penetrate from the anterior chamber of the eye into the vitreous body during inflammatory processes.

Changes in the lens with age:

1. cholesterol accumulates, the content of vitamins C and group B decreases, and the amount of water decreases;
2. the permeability of the lens bag deteriorates for nutrients(nutrition is disrupted);
3. the regulatory role of the central nervous system in maintaining the quantitative ratios of mediators - adrenaline and acetylcholine, ensuring a stable level of nutrient permeability;
4. The protein composition of the lens changes towards an increase in its insoluble fractions - albuminoids and a decrease in crystallins.

As a result of metabolic disorders in the lens, a dense nucleus forms in old age and its clouding occurs - cataracts. With loss elastic properties lens, the ability to accommodate decreases, develops presbyopia, or presbyopia.

The lens has no nerves and blood vessels, therefore it has no sensitivity and does not develop inflammatory processes. Exchange processes carried out through the intraocular fluid, which surrounds the lens on all sides.

Lens of the eye- This is the natural lens of the eye, located opposite the pupil. The most important element in the optical system of the eye.

It has a biconvex shape and is part of the light-conducting and light-refracting system of the eye. On both sides, the lens of the eye is attached to the ciliary body.

Interior the lens is adjacent to, and the outer part is facing the iris, . Normally, the lens of the eye is transparent. In the structure of the eye lens plays one of the main roles.

Lens structure and optical properties

The size of the lens is from 3.6 to 5 mm in thickness, and from 8 to 10 mm in thickness.

It contains several structures:

- capsule;
- capsular epithelium;
- basic substance.

The capsule is a thin, transparent shell of a uniform nature that covers the lens. She performs refractive and protective functions. The thickness of the capsule varies throughout its entire length. The capsule is thicker in front than in the back, since there is a single layer of epithelial cells.

Lens epithelium — is single-layer flat and non-keratinizing. Its main functions are nutritional, barrier and cambial.

Main substance– most of the lens consists of fibers, which are represented by elongated epithelial cells. Each of the fibers is transparent. The protein crystallin included in the substance allows it to be absolutely transparent. The substance does not contain blood vessels or nerves. Nourishes the lens aqueous humor and vitreous body.

The refractive power of the lens depends on the state, at rest the refractive power of the lens is about 19 diopters, and with the degree of maximum accommodation stress this figure increases to 33 diopters.

Diagnosis of the condition of the lens

Diagnostics functional state and the general condition of the lens is based on determining visual acuity and biomicroscopy of the anterior segment. Instrumental examination which is carried out by an ophthalmologist, allows you to determine the structure and size of your lens. The transparency of the lens and the presence of opacities and their location are also determined, which can have a negative impact on visual acuity.

Based on complaints and clinical signs perform biomicroscopy and optical coherence tomography. This allows us to evaluate the position of the lens in relation to the ciliary body and iris. The fact is that increased in diameter or height lens of the eye may be very closely adjacent to the ciliary body or leading to a narrowing of the anterior chamber angle. This is the main reason for the development of angle-closure glaucoma.

Treatment of lens diseases

The most effective treatment lens diseases surgery. IN medical practice drops are used to stop age-related clouding of the lens. But using these drops it is impossible to restore the transparency of the lens, and also to guarantee that the clouding will stop. The result of removing a clouded lens is full recovery patient.

There are different techniques, this can be extracapsular extraction, in which sutures are placed and phacoemulsification. The choice of technique is influenced by the degree of turbidity and its density, density ligamentous apparatus And the most important thing is the experience and qualifications of the doctor.

The lens is a biological formation that is part optical system in the organ of vision, which is involved in the process of accommodation. It looks like a biconvex lens, the refractive power of which averages approximately 20D; in a state of accommodation, the optical power increases significantly, often reaching 30-33D. The lens is placed inside the eyeball in the frontal plane between the iris and the vitreous body. Together with the iris, they make up the iridolens diaphragm, which divides eyeball on anterior section and rear.

The lens has anterior and posterior surfaces. In this case, the line limiting the transition of the front surface to the back is usually called the equator. The center of the anterior lens surface is called the anterior pole, the center of the posterior surface is called the posterior pole. The line that connects both poles is called the lens axis.

Dimensions and curvature of the lens

The radius of curvature of the anterior lens surface at rest of accommodation is 10 mm, the posterior one is 6 mm. The length of the lens axis is usually 3.6 mm. A narrow fissure separating the posterior lens surface from the vitreous body forms the retrolenticular or postlenticular space. In the eye, the lens is held in place by the ligament of zinn, which is formed by thin fibers. They are attached to it in the equatorial region. The other ends of the ligament of Zinn are attached to the processes of the ciliary body.

The lens capsule is the membrane covering it, which is transparent and elastic ocular tissue. The part of the capsule that covers the anterior surface of the lens is usually called the anterior capsule, the second part is called posterior capsule. The thickness of the anterior capsule tissue can range from 11 µm to 15 µm, and the posterior one - from 4 µm to 5 µm. Under the surface of the anterior capsule there is a single-layer cubic epithelium, reaching the equator of the lens and in this place, its cells become more elongated.

Layers of the lens

The germinal zone or growth zone of the lens is the equatorial zone of its anterior capsule; it is here that during a person’s life young lens fibers are formed from its epithelial cells.

The lens fibers are placed in the same plane and are connected to each other by a certain adhesive substance, forming radial plates. The glued ends of the fibers of adjacent plates form seams on the anterior and back surfaces lens When connected to each other, these seams create a lens star. The outer layers of its substance adjacent to the lens capsule (subcapsular layers) form the cortex of the lens, and the deep layers form its nuclear zone.

Lens proteins

Anatomical feature of the lens - complete absence it contains lymphatic and blood vessels, as well as nerve fibers. The lens consists of a protein substrate and water. Moreover, the share of water is approximately 65%, and proteins - almost 35%.

Normally, the lens substance includes nucleoprotein, mucoprotein, compounds of calcium, potassium, sodium, phosphorus, sulfur, magnesium, chlorine, traces of copper, manganese, iron, boron and zinc. Participants in its redox processes are the tripeptide glutathione and ascorbic acid. The lens also contains lipids, vitamins (A, B1, B2, PP) and other substances necessary for proper metabolism.

Metabolism occurs slowly in the lens through diffusion and osmosis. In this case, the lens capsule is assigned the function of semi-permeable biological membrane. Required for normal function The substance is brought into the lens by the intraocular fluid that washes the lens.

Age-related changes in the lens

The size, shape, transparency, and consistency of the lens undergo changes throughout human life. Thus, in newborns, the lens has an almost spherical shape, soft consistency and almost absolute transparency without color. In an adult, the shape of the lens transforms into biconvex lens with a flat front surface. Its color becomes yellowish, but transparency remains. The intensity of yellow in the shade of the lens increases with age.

By the age of 40-45, the core of the human lens becomes dense and it loses its former elasticity. By this age, accommodation weakens and presbyopia develops.

By about the age of 60, the ability to accommodate is almost completely lost. This is due to severe sclerosis of the lens nucleus - phacosclerosis. At this age, due to natural aging - deterioration and slowdown of metabolism, tissue respiration and energy metabolism, in different layers of the lens, opacities of varying severity and magnitude may appear, which are called senile cataracts. This disease is detected by examination using a slit lamp while dilating the pupil with mydriatic drugs.

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Many patients ask how to treat cataracts, which lenses are best to use? Cataracts - quite serious illness, which, if the development of the process is not stopped in time, can lead to complete blindness. But sometimes the patient’s condition worsens so much that medical indications lens removal is required.

In this case, the native lens is replaced by an artificial one. To create such optics, it is necessary to use high technology - the flexibility and transparency of the product are valued. It is important that the lens is fully implanted and lasts a long time.

In such operations, products from well-known foreign manufacturers are used. These lenses are as close in properties as possible to a natural lens. Each organ has certain physical parameters. Each lens made has its own optical power, and this value is calculated for each patient individually.

Which lens is better for cataracts is, of course, a controversial question; every specialist can say this. The main task is to conduct light and focus the image on the retina. But vision depends not only on the functions performed by the lens. The optic nerve, vitreous body, eye vessels and brain take an active part in this process. If they all fully perform their work, then visual acuity will be at the proper level, even with an artificial lens.

If these structures have any pathology, then vision will improve after surgery only partially, exactly as much as they can provide it. The surgeon cannot always fully determine in advance all the changes that have occurred in the retina and optic nerve, since they are hidden by cataracts until the time of surgery. Therefore, the cataract is removed in any case, and the degree of vision change and future forecasts are left for later, when the postoperative period has passed.

For urgent medical reasons, cataracts are removed if the lens swells or there is a stable high level in the eye. intraocular pressure.

Visual acuity, of course, depends on the quality of the artificial lens of the eye. Typically, a clouded lens that cannot be removed must be removed. sufficiently let light pass through. Artificial lens is nothing more than an intraocular lens, or IOL. This lens is designed in such a way that it can refract light rays and create an image on the retina.

The first lenses, when the technology for such operations was just being developed, had a high degree of rigidity. Very often they did not take root and were rejected by the eye. Such lenses could not change their shape, so to install them the surgeon had to make a fairly significant incision.

Also, the technology for replacing such a lens required sutures. Modern lenses are much more advanced than the old ones. The operation to replace the lens is very quick. It only takes 15 minutes to complete it completely. Then the patient can safely go home.

Modern lenses have a high degree of flexibility, to the point that they can be rolled up. Thanks to this ability, large incisions are not made during the operation, but are limited to microscopic ones. The size of the incision itself is so small that stitches are not required at all.

The lens itself completely unfolds in the eye. The material used for its production is fully compatible with eye tissues. But, despite all these innovations, complications from installing the product sometimes occur. Therefore, when choosing a suitable lens, it is necessary to take into account some nuances. In this case, the result obtained will be optimal and it will be possible to obtain the highest visual acuity.

Which lens is better?

The choice of a particular lens is influenced by whether the patient is farsighted or nearsighted before surgery. In the same way, any eye pathology that occurred before surgery affects the choice of lens. In any case, at the initial stage, comprehensive preparation for the operation is carried out, during which the patient undergoes a full examination.

After receiving the relevant data, the parameters of the required lens are calculated. As a result, a person who has long suffered from myopia or farsightedness can get rid of these vision defects.

The lens is installed for life. The patient does not feel its presence in any way. Only a special medical examination can reveal it. Therefore, you should not hope that when you come to the pharmacy or specialized center, you can buy any one you like and ask your doctor to install it.

Lens implantation is a very responsible procedure. Although the operation is underway only 20 minutes, it is necessary to replace the clouded lens very efficiently. A person’s vision and his future life will depend on the result of this work. Therefore, the choice should only be made by a specialist.

When choosing lenses, almost all clinics give preference to flexible intraocular lenses. They are manufactured in the USA, England and Germany and are fully compatible with the tissues that will surround them after lens implantation. And this means that there will be no negative reactions from the body, if there is a similar lens. It is their fault that eye degeneration will not occur.

A special feature of these models is the presence of ultraviolet and yellow filters. These filters are responsible for protecting the eyes from harmful rays of the sun.

Models and types of lenses

There are two types of flexible lenses:

• spherical;
• aspherical.

The latter are considered more reliable and provide best quality vision, not only during the day, but also at night, in the dark, when the amount of light is greatly reduced.

Aspheric lenses are flat and refract rays with the same coefficient anywhere on their surface. Thanks to this device, these lenses provide almost perfect vision.

According to many doctors, when replacing a lens, it is best to use an aspherical monofocal lens. Such a lens will provide good vision for long and medium distances.

At close distances you will need glasses. Such lenses are recommended for those patients who have to drive, as they prevent them from being blinded by the headlights of oncoming traffic. These lenses also render colors and contrasts quite well.

Lenses are also divided into:

• toric;
• monofocal;
• multifocal.

Toric ones are installed in those patients who suffered from astigmatism before surgery. Before the appearance toric lenses Problems arose with the treatment of such patients. Now the operation not only eliminates problems with the lens, but also eliminates astigmatism.

Monofocal lenses can improve vision when viewing distant objects. Therefore, the patient will need glasses when reading. Such lenses do not have the ability to switch vision from far to near.

Multifocal lenses are universal. They make it possible to see well at any distance, both far and near. Over the years, the native lens becomes less plastic; it is already difficult for it to change its shape, depending on where a person looks.

Multifocal lenses have a special design that allows you to completely simulate the changes occurring in the lens. Therefore, these lenses allow you to completely get rid of glasses.

Selection of lenses and their composition

When choosing a lens when replacing a lens, you need to choose one that will provide excellent vision at any time of the day and at any distance. Ideally, such a lens should make such corrections to vision that the patient will stop using glasses. Such lenses are produced by German companies. They are installed not only when replacing the lens, but also in case of serious age-related changes vision.

Before the advent of lenses, people were forced to wear glasses with very thick plus glasses.

Now it’s worth saying a few words about hard lenses. Their size equal to the sum the lens itself and its supporting apparatus. The largest rigid lenses can be up to 12mm. In order to implant such a lens, a significant incision will need to be made. Such interference cannot but affect general condition cornea.

The risk of complications increases several times. Nowadays, such lenses are implanted extremely rarely and in exceptional cases. Therefore, preference is given to lenses made of silicone, hydrogel, and acrylic. All these materials are based on hydrocarbon compounds. Thanks to this, they gain the valuable property of changing their shape without deformation.

Many patients who have already established soft lenses, speak about them with special respect. They note that after the operation their vision was restored very quickly, which could not but affect their quality of life.

Those patients who had lenses installed were especially pleased yellow color, which can protect against harmful radiation from monitors. Those people who have to spend a lot of time at the computer have received additional protection. Such lenses prevent the development of dystrophic processes.

How is the lens of the eye replaced for cataracts, which lenses are best to use? This question is asked by everyone who has to similar operation before our eyes. Artificial analogues of the lens are very diverse. They have different sizes, prices vary in rigidity and shape.

Make sense of this diversity to an ordinary person very difficult, so it would be better to trust the choice of an ophthalmologist who, based on his knowledge, will be able to make a good choice.

Video

The lens is an element that is responsible for the refraction of light rays before their further projection onto the retina. Thanks to this, a person can see surrounding objects. This part visual system is formed in the first weeks of embryo development. The eye lens gives vision the ability to focus on distant and nearby objects when located at one point in space.

Physically, the structure of the eye lens can be compared to a strong lens, convex on both sides. Its back and front surfaces have different radii of curvature. That is, it is flatter in front than in the back.

Location of the lens in the eye

The size of the lens in an adult is about 10mm. Center points back and front eye lens are called poles. A conventional line that runs from one pole to another is called an axis. Its length ranges from 3.6 to 5 mm. Simply put, the axis is the thickness of the lens. In a newborn optical lens The shape of the eyes is close to a ball; with age it becomes longer. As you get older, the power of light refraction by the lens decreases. This explains the unfocused gaze in infants.Behind the lens is the vitreous body. In front it is adjacent to the iris and chambers of the eye.

Adaptability of vision to focusing on distant and near objects is made possible due to the elasticity of the lens. It has this property due to its structural features. Lens surface human eye covers a transparent capsule, which is also called the “lens sac”. Its anterior part is lined from the inside with epithelium, which, when dividing and multiplying, allows the lens to grow. The fibers of the ligaments of the ciliary body of the eye are attached to it. This allows you to reliably fix the lens motionless on the visual axis, and also change the radius of curvature. This ensures clear, clear vision.

Transparency of the lens is given by special proteins - crystallins. Consistency internal substance soft, gelatinous. Inside there is a core, which is covered on top with cortex - cortical layers. The whole structure is similar in structure to an onion.

The lens has no blood vessels and nerve endings and consists of the following parts:

• Capsule

This is an elastic transparent shell of a homogeneous structure. It refracts light rays and also performs a mechanical function - it protects the lens substance from exposure external factors. The capsular bag is attached to the ciliary belt.

The thickness of the lens shell is not the same around the entire circumference. In front it is thicker due to the location of a layer of epithelial cells underneath it. In concentric circles, the so-called “belts,” the greatest thickness of the capsule is in the places where the ciliary belt is attached. Most thin layer- in the region of the posterior pole.

The capsule is semi-permeable, so it does not interfere with exchange in the lens.

The structure of the eye lens

• Epithelial layer

The epithelium is localized on the inner anterior part of the capsule and is located in one layer. Its cells are flat and do not have a stratum corneum.

It acts as a barrier and also ensures the absorption of nutrients. Lens fibers grow from epithelial cells. Then radial plates are formed from fibers of one row. This process occurs throughout life, so the thickness of the lens increases in old age. In the area of ​​the pupils, cells divide with little activity, so there is no active growth there.

• transparent substance

In addition to water, the substance contains proteins. U healthy person the contents of the lens are completely transparent, but in some diseases it chemical composition changes and it becomes cloudy. At the same time, vision deteriorates.In the center the substance is denser than at the periphery near the capsule.

Symptoms of lens damage

As a person ages, the nucleus and cortex become denser, and the eye lens is less and less able to change the radius of its curvature. The ligamentous apparatus also malfunctions, it does not stretch well, and the ligament attached to the lens becomes less elastic. Having crossed the age limit of 40-50 years, a person who previously had perfect vision begins to notice that his vision has become worse and it is more difficult for him to read. Letters blur before your eyes, and the image on the screen or monitor looks blurry.

To determine the condition of the lens, the doctor performs diagnostics using a biomicroscope.

The cause of deterioration in the condition of the lens may be blunt trauma eyes or presence concomitant disease, for example, glaucoma. IN the latter case the lens becomes cloudy faster than it would happen in the same person with age-related changes.

Diagnosis of pathologies of the eye lens

The basis of diagnosis, which allows us to determine the pathology of the lens or its ligamentous apparatus, is biomicroscopy of the anterior segment and testing of visual acuity. Using the device, the ophthalmologist checks the following parameters in the patient:

• Lens size;
• Presence and localization of opacities;
• Degree of transparency;
• Integrity and disturbances in the structure of the lens.

To examine the eyes in more detail, pupil dilation may be necessary. In some cases, this measure may temporarily improve vision. This happens because the diaphragm begins to transmit light through the opened transparent areas.

In case of deviations from the norm, parameters such as thickness or length can cause an excessively tight fit of the lens to the ciliary body or iris of the eye. In this case, the angle of the anterior chamber narrows. Because of this, the outflow of fluid contained inside the eye worsens. This can result in a narrow angle. In order to assess the location of the lens, ultrasound microscopy or optical tomography is used.

Types of lens diseases and their treatment

Lens pathologies can be congenital. Due to certain diseases, the optical lens of the eye may have incorrect position, including due to weak ligamentous apparatus. Cloudy areas may be localized in the nucleus or cortex (periphery). This reduces vision.

The most common diseases affecting the lens are cataracts and glaucoma.

Age-related clouding can be stopped or slowed down with the help of special drops, but changes that have already occurred cannot be corrected by such a measure. Usually the lens is restored surgically. If there is a significant deterioration in the condition of this part of the eye, complete replacement to an artificial analogue - intraocular lens. Surgery on your own lens does not guarantee complete elimination of opacification and the surgeon cannot guarantee that this process will be stopped in the future.

Lens cataract

Cataracts are removed using various techniques. The option is selected individually for each patient depending on the state of health, the presence of contraindications, the degree of the disease, the density and turbidity of the eye lens, financial opportunities patient, qualifications of an ophthalmologist.

This could be, for example, intra- or extracapsular extraction, in which surgeons remove the lens with or without a capsule, then replace it with an implant, and subsequently suture the cornea. Or you can resort to less traumatic, but more expensive phacoemulsification, in which minimal tunnel incisions are made, which are then sealed independently.

Also among the pathologies of the eye lens there is ectopia. It is expressed in the displacement of the lens, both within the pupil zone and beyond its borders. Its causes may be tumors, myopia high degree, injuries, overripe cataract. Also, this disease may be associated with congenital underdevelopment of the ligamentous apparatus of the eye, when the ligament is weak or partially lacks fibers. The consequences of this pathology include complications such as astigmatism, uveitis, and refraction. Due to the fault of the latter, a person may experience optical defects.

There is also such a pathology as. This condition is also called “lazy eye syndrome”. In this case, the brain, if there are any problems with the eye, “turns off” it from the visual process in order to avoid double vision. As a result of constant suppression of vision function, there is a risk of its complete loss.

Anomalies of the lens of the eye

The lens may have abnormal shape. In this case, the patient may be diagnosed with one of the following pathologies: lenticonus, coloboma, microphakia, biphakia (double lens) or aphakia (complete absence), spherophakia. In case of such structural disorders, the patient is prevented from complications such as amblyopia.

With microphakia, the crystal lens may become pinched or even fall out. In this case, intraocular pressure increases and strong pain. In this situation, the lens is immediately removed.

Abnormal condition of the lens and iris

With an anomaly such as spherophakia, the lens remains in the shape of a ball, without stretching out in shape. This pathology is usually hereditary and is combined with dislocations, secondary or microphakia. The anterior chamber of the eye is deep. The patient is often diagnosed at the same time. With this pathology, only the consequences and complications are treated. The underlying cause cannot be treated.

In a pathology called “biphakia” in medicine, the patient has two lenses of different sizes in the eye. They can be located in different planes. This phenomenon is extremely rare. It is caused by delayed regression certain vessels, which in the prenatal period put pressure on the lens of the embryo.

Coloboma is rare in patients and is caused by a hereditary factor. This pathology is encoded in a person’s genetic code and his relatives also have this phenomenon in their anamnesis. Wherein anomalous phenomenon in the area of ​​the equatorial edge of the lens there is a lack of one piece, a small part that should normally be present. The missing segment has the shape of an ellipse, a triangle, or may be crescent-shaped. There is usually one coloboma in the eye, less often - two. If it is small, it usually does not affect visual acuity. Otherwise, myopia or lenticular lens may appear. With this pathology, the lens itself retains its transparency. A patient with coloboma is most often prescribed optical correction of refractive errors and amblyopia prevention.

Lenticonus is an anomaly that occurs after an eye injury or is congenital. It is characterized by a change in the surface shape of the lens. This pathology is localized in one eye, inside, behind or in front. With this anomalous phenomenon, one can observe a cone-shaped or spherical protrusion towards the anterior chamber, its own thickness or the vitreous body of the eye.

Lens removal is indicated only when large sizes lenticonus. In other cases, they carry out treatment courses with the help and dilation of the pupil with medications. Pathology can cause a decrease in visual acuity or cause amblyopia.