Dystrophy of the eye

The dystrophy of the eye includes a variety of degenerative pathologies affecting its cornea - the transparent part of the outer shell, the retina - the inner membrane with photoreceptor cells, as well as the vascular system of the eyes.

The most important part of the eyes is the retina, because it is an element that perceives the light impulses of the visual analyzer. Although it is possible to imagine normal vision without a healthy cornea - a light-refracting lens of the eye providing at least two-thirds of its optical power. As for the blood vessels of the eyes, the fact that vascular ischemia can provoke a significant impairment of vision speaks of their far from last role.

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Causes of dystrophy of the eye

Now in the same order we will consider the causes of dystrophy of the eye.

As you know, there are no blood vessels in the cornea itself, and the metabolism in its cells is provided by the vascular system of the limbus (the growth zone between the cornea and sclera) and the liquids - intraocular and lacrimal. Therefore, for a long time it was believed that the causes of corneal dystrophy of the eye - structural changes and reduced transparency - are associated exclusively with violations of local metabolism and, in part, innervation.

Now, the genetically determined nature of the majority of cases of corneal degenerations, which are transmitted according to the autosomal dominant principle, is recognized and manifested at different ages.

For example, the result of mutations in the KRT12 gene or the KRT3 gene, which provide the synthesis of keratin in the corneal epithelium, is Mesmann's degeneration of the cornea. The cause of development of spotted corneal dystrophy lies in the mutations of the gene CHST6, which violates the synthesis of polymeric sulfated glycosaminoglycans that make up the corneal tissues. And the etiology of the dystrophy of the basal membrane and the Bowman membrane of type 1 (corneal dystrophy Reis-Bucklers), granular and latticed dystrophy is associated with a malfunction of the TGFBI gene responsible for the growth factor of the corneal tissues.

To the main causes of the disease, ophthalmologists include, first, biochemical processes in the membranes of its cells, associated with an age-related increase in lipid peroxidation. Secondly, the deficiency of hydrolytic lysosome enzymes, which contributes to the accumulation in the pigment epithelium of the granular pigment lipofuscin, which disables photosensitive cells.

It is especially noted that diseases such as atherosclerosis and arterial hypertension - because of their ability to destabilize the state of the entire vascular system - increase the risk of central retinal dystrophy by three and seven times, respectively. According to ophthalmologists, an important role in the development of degenerative retinopathy is played by myopia (shortsightedness), in which the eyeball stretches, the inflammation of the choroid of the eye, and the increased level of cholesterol. The British journal of ophthalmology in 2006 reported that smoking three times increases the risk of developing age-related retinal dystrophy.

After the fundamental research of the last two decades, the genetic etiology of many dystrophic changes in the retina has been revealed. Autosomal dominant gene mutations provoke excessive expression of the transmembrane G protein of rhodopsin, the key visual pigment of rod photoreceptors (rods). It is the mutations of the gene for this chromoprotein that explain the defects of the phototransduction cascade in pigmentary degeneration of the retina.

Causes of the disease may be associated with impaired local circulation and intracellular metabolism in hypertension, atherosclerosis, chlamydia or toxoplasmosis uveitis, autoimmune diseases (rheumatoid arthritis, systemic lupus erythematosus), diabetes mellitus of both types, or eye trauma. There is also a suggestion that problems with blood vessels in the eyes are a consequence of cerebrovascular damage.

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Symptoms of eye dystrophy

Ophthalmic symptoms of corneal dystrophy include:

• painful sensations of varying intensity in the eyes;
• feeling of contamination of the eye (presence of a foreign object);
• painful sensitivity of the eyes to light (photophobia or photophobia);
• excessive lacrimation;
• hyperemia of the sclera;
• swelling of the cornea;
• Reducing the transparency of the stratum corneum and reducing visual acuity.

With keratoconus, there is also a sensation of itching in the eyes and visualization of several images of single objects (monocular polyopia).

It should be borne in mind that the retinal dystrophy develops gradually and at the initial stages does not show any signs of itself. And the symptoms characteristic of degenerative retinal pathologies can be expressed as:

• rapid eye fatigue;
• temporary violations of refraction (hypermetropia, astigmatism);
• decrease or total loss of contrast sensitivity of vision;
• metamorphopsy (distortion of straight lines and distortion of images);
• diplopia (doubling of visible objects);
• niktalopiya (impairment of vision with reduced illumination and at night);
• appearance before the eyes of colored spots, "flies" or flashes of light (photopsy);
• distortions in the perception of color;
• absence of peripheral vision;
• cattle (the appearance in the field of view of areas not perceived by the eye in the form of darkened spots).

Central retinal dystrophy of the eye (age, vitelliform, progressive cone, macular, etc.) begins to develop in people with changes in the PRPH2 gene, which encodes the photoreceptor cells (rods and cones) providing photosensitivity to the membrane protein of the peripheral 2.

Most often the disease makes itself felt after 60-65 years. According to the American National Eye Institute (National Eye Institute), about 10% of people aged 66-74 years have the prerequisites for the appearance of macular degeneration of the eye, and in people aged 75-85 years this probability increases to 30%.

The peculiarity of central (macular) dystrophy consists in the presence of two clinical forms - non-exudative or dry (80-90% of all clinical cases) and moist or exudative.

Dry retinal dystrophy is characterized by the deposition of small yellowish clusters (druses) under the macula, in the subretinal area. The layer of photoreceptor cells of the yellow spot due to accumulation of deposits (metabolic products that do not split due to a genetically determined deficiency of hydrolytic enzymes) begins to atrophy and die off. These changes, in turn, lead to a distortion of vision, which is most evident in reading. Most often affected by both eyes, although everything can start with one eye, and the process lasts long enough. However, dry retinal dystrophy usually does not lead to a complete loss of vision.

Wet dystrophy of the retina is considered a more severe form, as it causes visual impairment in a short time. And this is due to the fact that under the influence of the same factors begins the process of subretinal neovascularization - the growth of new abnormal blood vessels under the yellow spot. Damage to the vascular walls is accompanied by the release of blood-serous transudate, which accumulates in the macular area and disrupts the trophism of the cells of retinal pigment epithelium. Vision is significantly deteriorating, in nine cases out of every ten there is a loss of central vision.

Ophthalmologists note that in 10-20% of patients the age-related retinal degeneration begins as dry, and then progresses to exudative form. Age-related macular degeneration is always bilateral, while in one eye there may be dry dystrophy, and in the second - wet. The course of the disease can be complicated by retinal detachment.

Retinal dystrophy in children

A sufficient spectrum of varieties of degenerative pathologies of the eye is represented by retinal dystrophy in children.

Central retinal dystrophy in children is a congenital pathology associated with mutation of genes. First and foremost, this is Stargardt's disease (juvenile macular disease, juvenile macular degeneration) - a genetically determined disease associated with a defect in the ABCA4 gene, inherited by the autosomal recessive principle. Statistics of the Royal National Institute of the Blind (RNIB) indicate that this disease accounts for 7% of all cases of retinal dystrophy in British children.

This pathology affects both eyes and begins to appear in children after five years. It manifests itself in photophobia, decreased central vision and progressive color blindness - dyschromatopsia in green and red.

To date, this disease is incurable, since the optic nerve is atrophied over time, and the prognosis is usually unfavorable. However, active rehabilitation steps can maintain and maintain a certain level of visualization (no more than 0.2-0.1).

With Best's disease (macular macular degeneration), which is also congenital, a fluid-containing cyst-like formation appears in the central fossa of the macula. This leads to a decrease in the sharpness of the central vision (blurry images with darkened areas) while maintaining peripheral vision. Patients with Best's disease often have almost normal vision for many decades. This disease is inherited, and often family members may not know that they have this pathology.

Juvenile (X-chromosomal) retinosis - splitting of the layers of the retina, followed by damage and degradation of the vitreous humor - leads to loss of central vision, and in half of the lateral cases. Frequent signs of this disease are strabismus and involuntary eye movements (nystagmus); the majority of patients are boys. Some of them retain a sufficient percentage of sight in adulthood, while others have a significant impairment of vision as a child.

Pigment retinitis includes several hereditary forms of the disease, which cause a gradual decrease in vision. Everything begins at the age of about ten years with the child's complaints about vision problems in the dark or the limitations of side vision. As ophthalmologists emphasize, this disease develops very slowly and extremely rarely leads to loss of vision.

Amberstein Leber - congenital incurable blindness, transmitted autosomally recessively, that is, to children born with this pathology, the mutated gene RPE65 should be in both parents. [More information - when we go to our publication Amavroz Leber].

Retinal dystrophy in pregnancy

Possible dystrophy of the retina during pregnancy threatens women with severe myopia (above 5-6 diopters), since the shape of the eyeball is deformed. And this creates the prerequisites for the development of complications in the form of peripheral vitreochorioretinal dystrophies, which can cause ruptures and detachment of the retina, especially during childbirth. That is why in such cases midwives perform a cesarean delivery.

In pregnant women with myopia - in the absence of complications (gestosis) - the retinal vessels are slightly narrowed to support blood circulation in the uterus-placenta-fetus system. But when pregnancy is complicated by increased blood pressure, soft tissue swelling, anemia and nephrotic syndrome, narrowing of the retinal vessels is more pronounced, and this causes problems with its normal blood supply.

According to ophthalmologists, peripheral dystrophy is most often a consequence of a decrease in the volume of circulating blood in all eye structures (by more than 60%) and a deterioration in the trophism of their tissues.

Among the most common retinal pathologies during pregnancy are: latticular dystrophy with thinning of the retina in the outer upper part of the vitreal cavity, pigmented and point-white retinal degeneration with sites of atrophy of the epithelium of the reticular membrane, as well as degeneration of the eye vessels with spasms of capillaries and venules. Quite often retinocystis occurs: the retina departs from the choroid of the eye (without rupture or with rupture of the mesh shell).

What is the dystrophy of the eye?

If you follow the anatomical principle, you must start with the cornea. In total, according to the latest international classification, corneal dystrophy of the eye counts more than two dozen species - depending on the localization of the corneal pathological process.

To superficial or endothelial dystrophies (in which amyloid deposits occur in the epithelium of the cornea) include the dystrophy of the basal membrane, juvenile dystrophy of Mesmann (Mesmann-Wilke syndrome), etc. Dystrophies of the second layer of the cornea (the so-called Bowman membrane) include Tiele-Benke subepithelial dystrophy, dystrophy Flight-booker and others; over time, they often go into the surface layers of the cornea, and some can affect the intermediate layer between the stroma and endothelium (Descemet's membrane) and the actual endothelium.

Dystrophy of the cornea with localization in the thickest layer, consisting of collagen fibers, fibro- and keratocytes, is defined as stromal dystrophy, which can be different in the morphology of lesions: lattice, granular, crystalline, spotty.

In the case of damage to the inner layer of the cornea, endothelial forms of the disease (Fuchsa, spotted and posterior polymorphic dystrophy, etc.) are diagnosed. However, with the cone variety of dystrophy - keratoconus - degenerative changes and deformation occur in all layers of the cornea.

Dystrophy of the retina in domestic ophthalmology in the place of origin is divided into central and peripheral, and by etiology - to acquired and conditioned genetically. It should be noted that to date, with the classification of retinal dystrophy, there are many problems that lead to the multivariate terminology. Here is just one, but very illustrative example: central retinal dystrophy can be called age, senile, central chorioretinal, central chorioretinitis, central involutional, age-related macular degeneration. While Western specialists, as a rule, dispense with a single definition - macular degeneration. And this is logical, because the macula (macula in Latin is a spot) is a macula lutea in the central retina that has a depression with photoreceptor cells that convert the effect of light and color into a nerve impulse and send it through the visual cranial- brain nerve to the brain. Age-related retinal dystrophy (in people older than 55-65 years) is perhaps the most common cause of vision loss.

Peripheral dystrophy of the retina is represented by such a list of "modifications" that, under conditions of terminological disagreement, it is quite problematic to bring it to its full extent. This pigment (taperotinatal or pigment retinitis), cone-rod, Vitreoretinal dystrophy Goldman-Favre, Leber's amaurosis, Lefler-Wadsworth 's dystrophy, white-spotted retinitis (spot-white), etc. Peripheral dystrophy can cause rupture and detachment of the retina.

Finally, the dystrophy of the vessels of the eye, which can affect the eye artery and branch off from it the central artery of the retina, as well as the veins and venules of the eyes. First, pathology manifests itself in microscopic aneurysms (extensions with protruding walls) of extremely thin blood vessels of the retina, and then can progress to proliferative forms, when neovascularization begins in response to tissue hypoxia, that is, the growth of new, abnormally fragile blood vessels. In themselves, they do not cause any symptoms, but if the integrity of their walls is disturbed, serious vision problems occur.

Diagnosis of eye dystrophy

In ophthalmological clinics, diagnosis is carried out using such methods and techniques as:

• visocontrastometry (determination of visual acuity);
• perimetry (visual field study);
• campimetry (determining the size of a blind spot and location of cattle);
• Functional testing of the central field of view using the Amsler grid;
• testing of color vision (allows to determine the functional state of cones);
• testing adaptation to darkness (provides an objective picture of the functioning of rods);
• ophthalmoscopy (examining and assessing the condition of the fundus);
• electrooculography (gives an idea of the movements of the eyes, the potential of the retina and the muscles of the eye);
• Electroretinography (determination of the functional state of various parts of the retina and the visual analyzer);
• fluorescent angiography (allows visualization of the blood vessels of the eye and detect the growth of new blood vessels and leakage from existing vessels);
• tonometry (measuring the level of intraocular pressure);
• US of internal structures of the eye in two projections;
• optical layered tomography (examination of the structures of the eyeball).

For the diagnosis of corneal dystrophy, the eyes are necessarily inspected with a slit lamp, pachymetry (to determine the thickness of the cornea), skiascopy (to determine the refraction of the eye), corneotopography (to determine the degree of curvature of the corneal surface), and confocal biomicroscopy.

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Treatment of dystrophy of the eye

Symptomatic treatment of corneal dystrophy of the eye includes medications to improve the trophism of its tissues:

Taufon - 4% eye drops based on taurine, which contributes to the restoration of tissues damaged by degenerative changes in the cornea. They should be instilled under the conjunctiva - 0.3 ml once a day, the course of treatment - 10 days, which repeats in six months. Taufon in the form of a solution for injection is used in more severe cases.

Drops Sulfated glycosaminoglycans (Balarpan) due to the content of the natural component of the corneal stroma activates its regeneration. It is prescribed two drops in each eye in the morning and in the evening - for 30 days. Stimulate the interstitial energy metabolism and restoration of the damaged cornea of Oftan Katachrom Drops, consisting of adenosine (ATP component), nicotinic acid and cytochrome oxidase enzyme; recommended by doctors dosage - three times a day for 1-2 drops by instillation, that is, in the conjunctival sac (tilting the head back and slightly pulling the lower eyelid).

In addition, magnetophoresis with Vita-Yodurol drops is used, which, in addition to nicotinic acid and adenosine, contain magnesium and calcium chlorides.

Treatment of retinal dystrophy

At first, treatment with drugs is aimed at stimulating local blood circulation - to improve the nutrition of tissues (the drops given above are prescribed).

For example, such treatment of retinal pigmentary dystrophy is carried out twice a year, but, according to experts, most often it does not give the desired effect. The last word is left for ophthalmic microsurgery: operations are performed to insert a longitudinal flap of one of the six oculomotor muscles into the vascular region of the eye.

Treatment of retinal dystrophy of the eye localized in the macular area should take into account not only the etiology of the disease and accompanying and aggravating diseases of the individual patient, but also the pathology form - dry or exudative.

Adopted in domestic clinical practice, the treatment of dry retinal dystrophy can be performed with antioxidant drugs. One of them is Emoxipine (in the form of 1% and eye drops and injection solution). The solution can be injected through the conjunctiva or the eye area: once a day or every other day, the maximum course of treatment lasts a month.

In the treatment of retinal dystrophy with drugs that neutralize free radicals and prevent the damage of cell membranes, the antioxidant enzyme superoxide dismutase, which is part of the Ereiside drug (in the form of a powder for the preparation of drops), is used. These drops should be prepared on distilled water and dig in at least 10 days - two drops three times a day.

Wet dystrophy of the retina is treated by photodynamic therapy. This is a combined non-invasive method aimed at stopping the process of neovascularization. To do this, the patient is injected intravenously with the photosensitizing agent Visudin (Verteporfin), which, after activation by a cold red laser, causes the production of singlet oxygen, which destroys rapidly proliferating cells of the walls of abnormal blood vessels. As a result, cells die, and there is a tight occlusion of newly formed vessels.

Ophthalmologists use drugs blocking the VEGF-A protein (Vascular Endothelial Growth Factor), produced by the body for the growth of blood vessels, for the treatment of macular degenerative pathologies of the exudative type. Suppress the activity of this protein preparations such as Ranibizumab (Lucentis) and Pegaptanib sodium (Makugen),

Which are injected into the vitreous humor of the eye 5-7 times during the year.

And intramuscular injection of the synthetic hormone of the adrenal cortex of Triamcinolone acetonide helps normalize catabolism in the connective tissue, reduce the level of cell division of membrane proteins and stop infiltration in wet retinal dystrophy.

Treatment of retinal dystrophy with laser

It should be borne in mind that laser treatment can not return normal vision, since it has another purpose - to slow the progression of the disease and minimize the risk of detachment of the retina. Yes, while it is impossible to revive dead cells-photoreceptors.

Therefore, this method is called peripheral prophylactic laser coagulation, and the principle of its action is based on the clotting of proteins of retinal epithelial cells. This way it is possible to strengthen the pathologically altered sections of the retina of the eye and prevent the separation of the inner layer of photosensitive rods and cones from the pigment epithelium.

This is how the peripheral retinal dystrophy of the eye is treated by laser coagulation. And laser therapy for dry dystrophy is aimed at removing deposits from the subretinal zone of the eye.

In addition, laser coagulation seals choroidal neovascularization with macular degeneration and reduces the growth of "flowing" blood vessels, preventing further deterioration of vision. After such treatment there is a scar that creates a permanent blind spot in the field of vision, but it is much better than a solid blind spot instead of vision.

By the way, no alternative remedies for retinal dystrophy should be used: they will not help anyway. So do not try to be treated with infusion of onion husk with honey or lotions with a decoction of chamomile and nettle ...

Vitamins and nutrition in retinal dystrophy

Very important are the "right" vitamins for retinal dystrophy. They include all the vitamins of group B (especially B6 - pyridoxine), as well as ascorbic acid (antioxidant), vitamins A, E and P.

Many eye doctors recommend taking vitamin complexes for vision containing lutein - carotenoid natural yellow enzymes. Not only does it have strong antioxidant properties, it also reduces the formation of lipofuscin involved in the emergence of central retinal dystrophy. Our organism can not independently produce lutein, so it must be obtained with food.

Eating with retinal dystrophy can and should help fight, and best of all - to prevent the dystrophy of the eye. For example, most of all lutein contains spinach, parsley greens, green peas, broccoli, pumpkin, pistachios, egg yolk.

It is necessary to include in your diet fresh fruits and vegetables in sufficient quantities, healthy unsaturated fats of vegetable oils and whole grains. And do not forget about the fish! Mackerel, salmon, sardines, herring contain omega-3 fatty acids, which can help reduce the risk of vision loss associated with macular degeneration. These acids can also be found in ... Walnuts.

Prognosis and prevention of dystrophy of the eye

The prognosis of eye dystrophy - due to the progressive nature of this pathology - can not be considered positive. However, according to foreign ophthalmologists, retinal dystrophy alone will not lead to complete blindness. In almost all cases, a certain percentage of the view, mostly peripheral, remains. One must also take into account the fact that you can lose sight, for example, with a severe form of stroke, diabetes or trauma.

According to the American Academy of Ophthalmology, in the US, only 2.1% of patients with central retinal dystrophy have completely lost their sight, while the rest have maintained a sufficient level of peripheral vision. And yet, despite its successful treatment, macular degeneration may reappear with time.

Prevention of eye dystrophy is a healthy way of life. Promote macular degeneration of the eye maculae by consuming large amounts of animal fats, high cholesterol and metabolic disorders in the form of obesity.

The role of oxidative stress in retinal cells in the development of her dystrophy convincingly demonstrates the increased rate of development of pathology in smokers and those exposed to UV irradiation. Therefore, doctors advise their patients to quit smoking and avoid exposure to the cornea of intense sunlight, that is, wearing sunglasses and hats.

And the elderly are useful to visit the ophthalmologist once a year, especially if there is a dystrophy of the eye in the family history - the retina, the cornea or the vessels.