Sclera - outer layer eyeball, which covers 5/6 of its area. Due to high density tissue, the sclera acts as a kind of opaque capsule with variable thickness.
The structure of the sclera
The structure of the sclera has three layers:
- The outer one, which is called the episclera;
- Middle, or sclera itself;
- Internal (brown plate).
The episclera has a large number of blood vessels that deliver oxygenated blood. In the upper regions, the blood flow is more powerful than in the remaining parts. This pattern is due to the fact that most of the vessels come from the muscle fibers of the anterior part of the eyeball.
The middle layer contains many collagen fibers and fibrocytes. The latter produce collagen as needed.
The brown plate contains a large amount of pigment, which gives a specific color to the tissues of this layer. Pigment cells that are found in the inner layer of the sclera are called zoromatophores. The endothelium is located on top of the brown plate.
The sclera is penetrated throughout its entire thickness by nerve fibers and vascular bundles, which pass through special channels (emissaries).
Physiological sclera
The main role of the sclera is protective, it warns Negative influence external factors(mechanical and physical) on the internal structures of the eye. This ensures normal functioning of the eye and clear vision of objects. In addition, some muscle fibers are attached to the sclera, which help the eye move when studying the external world. This important function of the sclera is called support.
Video about the structure of the sclera of the eye
Symptoms of scleral damage
Scleral disease is characterized by the appearance of the following symptoms:
- Scleral rupture;
- Formation of dark spots on the surface;
- Decreased overall visual acuity;
- Changes in the structure of collagen fibers.
Diagnostic methods for scleral lesions
To identify pathology when scleral disease is suspected, perform the following manipulations:
- External visual inspection;
- eyes;
- eyes using a microscope.
Once again, it should be recalled that the main function of the sclera is protective, due to which it protects the eye from mechanical influence and negative environmental factors. In this regard, it is very important to care for this structure of the eye properly and undergo examinations by doctors to identify pathologies.
Diseases of the sclera
Due to the fact that the sclera protects the eye from external influences and provides a supporting function, disruption of its functioning negatively affects the entire optical system. Among scleral diseases, the following groups are distinguished:
- Congenital (in particular, melanosis);
- Acquired (for example, staphyloma,).
As the thickness decreases, the color of the sclera changes. Sometimes this is due to a disorder in the hearing aid. With melanosis there are dark spots on the surface of the sclera.
When there is inflammation in the area of the eyeball, the process can affect other systems of the body, and therefore intervention is required.
is an inflammatory process that affects the entire thickness of the outer connective tissue membrane of the eyeball. Clinically manifested by hyperemia, vascular injection, edema, pain on palpation of the affected area or movements of the eyeball. Diagnosis of scleritis comes down to an external examination, biomicroscopy, ophthalmoscopy, visometry, tonometry, fluorescein angiography, ultrasound examination(Ultrasound) in B-mode, computed tomography. Depending on the form of the disease, the treatment regimen includes local or systemic use of glucocorticoids and antibacterial agents. With purulent scleritis, opening the abscess is indicated.
General information
Scleritis is an inflammatory disease of the sclera, characterized by a slowly progressive course. Among all forms, anterior scleritis is the most common (98%). Damage to the posterior parts of the sclera is observed in only 2% of patients. Options for the course of pathology without necrosis predominate over necrotizing ones, which is associated with a favorable prognosis. In rheumatoid and reactive chlamydial arthritis, diffuse variants of the disease are common. In 86% of cases of ankylosing spondylitis, nodular scleritis is diagnosed. In 40-50% of patients pathological changes sclera is combined with joint damage of inflammatory origin, and in 5-10% of cases arthritis is accompanied by scleritis. The disease is more common in females (73%). The peak incidence occurs between the ages of 34 and 56 years. In children, the pathology is observed 2 times less often.
Causes of scleritis
The etiology of scleritis is directly related to a history of systemic diseases. Triggers of scleral damage are rheumatoid arthritis, Wegener's granulomatosis, juvenile idiopathic, reactive chlamydial or psoriatic arthritis, polyarthritis nodosa, ankylosing spondylitis and polychondritis, characterized by a relapsing course. Less commonly, this pathology develops in postoperative period after surgical removal of pterygium or traumatic injury. Described clinical cases infectious scleritis in patients with a history of vitreoretinal surgery.
To scleritis infectious etiology often results from dissemination of the process from the area of ulceration on the cornea. Inflammation can also be a source of infection. paranasal sinuses nose The most common causative agents of the disease are Pseudomonas aeruginosa, Varicella-Zoster virus and Staphylococcus aureus. In rare cases, scleritis is of fungal origin. Drug-induced damage to the sclera more often develops when taking mitomycin C. Risk factors are a history of osteoarticular forms of tuberculosis, systemic inflammatory diseases.
Symptoms of scleritis
From a clinical point of view, ophthalmology distinguishes anterior (non-necrotizing, necrotizing), posterior and purulent scleritis. Non-necrotizing lesions of the sclera can be diffuse or nodular. Necrotizing may or may not be accompanied by an inflammatory process. In some cases, the course of scleritis is characterized by short-term self-terminating episodes. In the same time, pathological process in the sclera provokes its necrosis with the involvement of the underlying structures. For of this disease characterized by an acute onset; sluggish variants are less common. With diffuse scleritis, the entire anterior part of the outer connective tissue membrane of the eyeball is involved in the inflammatory process. Nodular lesions are accompanied by decreased visual acuity.
Anterior scleritis is characterized by a slowly progressive course. This form is accompanied by binocular damage to the organ of vision. Patients note severe pain when touching the area of edema projection, photophobia. A long course of the disease leads to damage to the sclera along the circumference of the limbus (ring-shaped scleritis) and the occurrence of severe keratitis, iritis or iridocyclitis. With purulent scleritis, rupture of the abscess membranes is possible, which leads to the development of iritis or hypopyon.
With necrotic damage to the sclera, patients note increasing pain, which later becomes constant, radiating to the temporal region, brow ridge and jaw. Pain syndrome not relieved by taking analgesics. Necrotizing scleritis is complicated by scleral perforation, endophthalmitis or panophthalmitis. In the posterior form of the pathology, patients complain of pain when moving the eyeball and limited mobility. Postoperative scleritis develops within 6 months after surgical intervention. In this case, an area of local inflammation is formed, which is replaced by necrosis. A decrease in visual acuity is observed only when the inflammatory process spreads to the adjacent structures of the eyeball or the development of secondary glaucoma.
Diagnosis of scleritis
Diagnosis of scleritis includes an external examination, biomicroscopy, ophthalmoscopy, visometry, tonometry, fluorescein angiography, B-mode ultrasound (US), computed tomography. An external examination of patients with anterior scleritis reveals swelling, hyperemia and vascular injection. The area of edema has defined boundaries. On palpation examination, pain is noted. Carrying out biomicroscopy for “jellylike” scleritis allows us to identify the area of overhang of the chemosed conjunctiva over the limbus. This area has a red-brown tint and a gelatin-like consistency. Infiltrates with pronounced vascularization can be found on the surface of the cornea. The method of biomicroscopy with a slit lamp for diffuse scleritis determines the violation of the physiological radial direction of the vascular pattern. In the nodular form, viziometry indicates a decrease in visual acuity.
With purulent scleritis, external examination reveals purulent infiltrate and vascular injection. Damage to the posterior parts of the sclera is accompanied by swelling of the eyelids, conjunctiva and slight exophthalmos. The prominence of the disc is determined by ophthalmoscopy optic nerve, subretinal lipid exudation, retinal and choroidal detachment caused by the accumulation of exudate. Ultrasound in B-mode indicates thickening of the posterior part of the outer connective tissue membrane of the eyeball, accumulation of exudate in Tenon's space. Changes in scleral thickness can also be confirmed using CT.
In case of necrotizing scleritis, fluorescein angiography is used to determine the tortuous course, areas of vascular occlusion, and avascular zones. Carrying out biomicroscopy with a slit lamp allows you to visualize necrotic changes in the sclera and ulceration of the adjacent conjunctiva. The dynamics reveal an expansion of the necrosis zone. Tonometry in patients with scleritis often reveals an increase in intraocular pressure (more than 20 mm Hg).
Treatment of scleritis
The treatment regimen for scleritis includes the local use of glucocorticoid and antibacterial drops for instillation. If the disease is accompanied by increased intraocular pressure, then the therapy complex must be supplemented with topical antihypertensive drugs. The course of treatment includes taking non-steroidal anti-inflammatory drugs. If they are intolerant, it is recommended to prescribe medications from the group of glucocorticosteroids. For scleritis without necrotic lesions, glucocorticoids and antibacterial drugs must be administered by subconjunctival injection. An alternative this method administration is the use of prolonged forms of glucocorticoids.
With the development of scleral necrosis, combination therapy with glucocorticosteroids and immunosuppressants is indicated. In cases where allergic reaction parallel with data medicines antiallergic and desensitizing drugs are used. At purulent form scleritis treatment tactics boil down to massive antibacterial therapy. In this case, oral and subconjunctival routes of administration of drugs from the group of fluoroquinolones, aminoglycosides and semi-synthetic penicillins are used. An additional method of administration is electrophoresis. If there is no effect of drug therapy, surgical opening of the abscess is indicated. Also, the treatment regimen should include drugs to treat the underlying pathology against which scleritis developed. If the etiological factor is Mycobacterium tuberculosis, anti-tuberculosis drugs for local application are considered as auxiliary.
Forecast and prevention of scleritis
Specific prevention of scleritis has not been developed. Nonspecific preventive measures boil down to timely treatment underlying pathology, prevention of inflammation of the paranasal sinuses (sinusitis), compliance with the rules of asepsis and antisepsis during surgical interventions. Patients with a history of systemic diseases need to be examined by an ophthalmologist 2 times a year. The prognosis for life and ability to work depends on the timeliness of diagnosis, the adequacy of treatment, the type of pathogen in the infectious lesion and the form of the disease. The most favorable option is diffuse forms of the disease. Scleritis caused by Pseudomonas aeruginosa often has a poor prognosis.
The opaque part of the fibrous membrane is the sclera of the eye. It covers 85% of all surfaces and is primarily responsible for transmitting visual information to the brain. The features of its structure provide wide range functions. With anomalies and the development of pathologies, there is a risk of vision loss. Problems with the sclera cause a number of characteristic symptoms; if they exist, you should consult a doctor. Treatment depends on the current disease and the stage of its development, in most cases it is applied drug treatment of a local nature.
Anatomy of the sclera
The sclera is the white membrane of the eye, located on the outside and, together with the cornea, represents fibrous tissue. Reaching the iris, it forms a dense protective ring. According to physical characteristics it has White color and an opaque structure, due to which a person has vision. This is a fairly dense tissue of several layers; normally the thickness of the sclera reaches up to 1 mm. Despite this structure, the protein membrane of the eyeball can stretch, but this property decreases with age.
Shell structure
Density is ensured due to anatomical features. The structure of the sclera is a very complex process. The main component is collagen, it is arranged in a chaotic manner, thus causing the opacity of the eye. Full functionality is possible thanks to the multilayered shell, with the layers of the sclera differing in composition and density:
The shell has a very complex and intricate structure.
- Outer layer. The thinnest ball, filled with a large number of blood vessels.
- Middle layer. It is also called scleral, it contains maximum amount collagen.
- Inner layer. Represents connective tissue in combination with the pigment part.
The visible part of the sclera is only the top layer, the subsequent ones are located inside, but when depleted, protrusion is possible. This process is observed in ophthalmic pathologies.
What functions does it perform?
The versatility of the shell is ensured by its complex structure. Each of the 3 layers plays its role and only a holistic effect guarantees full vision. All functions of the white membrane of the eye are quite diverse. First of all, we are talking about protecting the pupil from external damage. The sun has a negative effect on the condition of the eye. It is due to the refraction of light in the shell that the pupil does not dazzle and an image appears. In addition, the sclera performs the following functions:
The sclera makes it possible to move our eyes in the direction we need. - Untangles with fastenings for the vascular and muscular apparatus.
- Provides blood outflow through venous branches.
- Responsible for eye mobility.
- Conducts moisture through the venous sinus of the sclera.
- Provides safe passage of the nerve to the eyeball.
What does healthy sclera look like?
You can distinguish a diseased state of the protein sphere from a healthy one by color. In infancy, the sclera is thin, so the membranes appear blue. This condition is not considered pathological and goes away on its own over time. What color of proteins in an adult may indicate the genetic nature of the problem; dystrophic changes have formed at the intrauterine level.
Yellowness of the sclera indicates possible pathologies. At the same time, the shell looks dull and cloudy. Such changes may indicate the impact of an infection. Lesions are not only local; kidney disease affects the color of the proteins. In old age, there may be large quantities of fat cells in the eyes; they can change color to yellow.
Diseases
The organ is susceptible inflammatory processes which are caused by bacteria. Pathologies that develop in the eyes at the level of the sclera are most often of an inflammatory nature, provoked by infections. However, primary sources are not always located directly in the organ. Painful manifestations in the membrane of the eye can only act as symptoms of the main processes. First of all, the ophthalmologist looks for the main diseases of the sclera, these include the following:
- Scleritis. An inflammatory pathology in which the inner layers of the membrane are affected.
- Staphyloma. The disease is caused by destructive processes, as a result of which the membrane is depleted.
- Episcleritis. Damage to the upper layer, accompanied by the formation of nodules.
Developmental anomalies
Congenital disorders pose a significant risk pathological forms, they are difficult to diagnose and do not always respond to conservative treatment. These include blue sclera syndrome. This color may indicate insufficient iron in the blood. Often such a disease is not a single developmental deviation; other pathologies of the eyes, ears, and musculoskeletal system are also observed.
With an excess amount of melanin, the layers become yellow. One more congenital pathology is melanosis or melanopathy. This disease is also associated with pigmentation, only the membrane becomes yellow due to saturation with melanin. This process occurs as a result of a violation of carbohydrate metabolism. Changes in color may appear in different ways, with distinctive layers or spots appearing on the top layer.
The sclera of the eye is the largest membrane of the visual organ. It occupies up to 5/6 of the entire area. The thickness of the sclera varies in different places and in some places reaches 1 mm. The sclera is completely opaque, it has a matte white color. In young children, the thickness of this membrane is small, so the visual pigment shines through it, due to which the eye acquires a bluish tint. As the child grows, the thickness of this membrane increases.
The structure of the sclera and its functions
The sclera is the opaque covering of the visual organs. Due to the density and light resistance of the sclera, it is ensured good vision and normal intraocular pressure. This membrane serves to protect the visual organ from various types of damage.
This shell has several layers. The outer layer is literally penetrated by a vascular network, due to which good blood supply is ensured. This area is connected to the outer part of the eyeball. The capillaries pass through the muscle layer to the anterior part of the visual organ. The outer layer has more intense blood circulation than the inner areas.
The sclera consists of collagen and fibrocytes. This area is involved in the production of collagen and separates it into individual fibers.
The last layer is called brown. This layer acquired its name due to the content of a special pigment, which gives color to this area. This pigmentation is caused by special cells called chromatophores.
The entire thickness of the sclera is penetrated by the smallest blood vessels and nerve endings. This is a very sensitive shell.
Diseases
There are several diseases of the sclera of the eye that can lead to permanent vision impairment. This is due to the fact that this section of the visual organ performs several tasks at once important functions, and any violation persistently affects visual acuity. Diseases can be congenital or acquired and have different character. The most common acquired pathologies are:
If a person has sclera blue color, then this may be caused by improper formation of the connective tissues of the eyes in the womb. This attractive color is explained by the transparency of the layer and the fact that another pigment layer is visible through it. The cause of this pathology may be diseases of the joints and auditory organs.
Another disease of the sclera of the eye is melanosis. In this case, characteristic spots form on the surface of the shell dark color. People with such a deviation should be registered with an ophthalmologist - this is necessary to avoid various complications such as retinal detachment and visual impairment.
Inflammatory diseases of this membrane of the visual organ are quite common. Such ailments can be caused by disruption of work different organs both systems and infections. Any infectious diseases, regardless of their location, can be an impetus for the development of eye diseases. This is due to the fact that pathogens quickly spread throughout the body through the bloodstream.
A doctor can make a correct diagnosis in a particular case after a preliminary examination.
Diagnostic methods
Before starting treatment, it is necessary to correctly diagnose the disease. To do this, collect anamnesis and conduct an examination of the patient. If necessary, the membranes of the optic organs are examined under a microscope. In some cases, an ultrasound of the eyes is required.
To correctly assess the patient’s health, a detailed blood test is performed. In some cases, genetic counseling is necessary.
Symptoms for diseases of the sclera
Diseases occur with characteristic symptoms, which are easy to diagnose. Most often observed:
With melanosis of the eyes, dark spots form around the visual organs; most often they are smooth, but at times they rise slightly above the surface. They can spread to the skin around the eyebrows and forehead.
Congenital pathologies
Congenital diseases are indicated when the color of the sclera or its shape changes. Such diseases are genetic and are diagnosed extremely rarely. The pronounced blue color of the shell indicates such a pathology. Such patients have poor hearing and suffer from frequent bone fractures.
In this case, a color change is observed already at the birth of the child. In newborns with this anomaly, the blueness of the eyes is more pronounced than in healthy children, and does not go away by six months. The size of the eyes is usually not changed, but in addition to this, there may be other visual impairments - color blindness, cataracts, clouding of the cornea. 
In severe cases, children with this pathology die in the prenatal period. But it also happens that a child suffers from frequent bone fractures and only by adolescence such cases become fewer.
Cysts on the sclera can also be congenital or acquired. The latter occur after eye injuries and penetrating wounds. Cysts occur different sizes and shapes. They are immobile and grow rather slowly. In this case, the treatment is surgical; the cyst is removed classically or with a laser. If the posterior wall of the cyst is severely thinned, it is necessary to perform scleroplasty.
There are also tumors that affect this membrane. Such pathologies occur quite often and can be a complication of other oncological diseases. Problems with the sclera of the eye are often observed in patients with tuberculosis and diabetes.
Treatment in this case is mainly symptomatic, aimed at maintaining normal health.
Treatment
Any treatment should begin with a quality diagnosis. Initially, the cause that led to changes in the membranes of the eye is precisely determined. In some cases, it is enough to simply eliminate the root cause to normalize the patient’s condition. Treatment uses medications, physiotherapeutic procedures and surgical methods.
The patient is prescribed drugs to reduce intraocular pressure, as well as anti-inflammatory drops and ointments. Treatment is always carried out comprehensively.
If there is severe deterioration in vision or a retinal tear, then resort to surgical treatment. Strengthening the posterior pole of the eye is often used. In patients with staphylomas, the sclera is shortened and alloplasty is performed. If the cause of the disorder is glaucoma, then this disease is initially treated surgically.
After treatment, the patient remains registered with an ophthalmologist for some time. This allows you to timely identify various deviations and avoid complications.
Prevention of scleral diseases
The visual organs are very sensitive to any negative factors. In order to maintain good vision for many years, you must adhere to the following recommendations from doctors:
- Eat rationally. The daily menu should contain a lot of plant foods rich in vitamins and minerals.
- Avoid injury to the visual organs.
- Pregnant women should not self-medicate or take any medications without a doctor's prescription.
- At the first signs of visual disease, you should see an ophthalmologist.
- If the ophthalmologist has prescribed treatment, it should be carried out in the recommended course.
It is impossible to prevent genetic eye diseases, but before planning a pregnancy, it is advisable for parents who have vision problems to visit a geneticist. If a newborn is found to have congenital diseases eye, consultation with leading specialists is necessary.
Diseases of the sclera are not such a common occurrence, but they always lead to deterioration of vision. Treatment of such diseases requires a balanced approach. If conservative methods If they don’t give results for a long time, they resort to surgery.
