The blindness is a pathological state at which visual acuity is sharply reduced or completely is absent. Depending on a disease form the clinical symptomatology is presented by decrease in visual acuity, emergence of scotomas, violation of color perception, loss of nasal or temporal half of the visual field. Diagnosis of a blindness is based on results of a vizometriya, perimetry, an oftalmoskopiya, fluorescent angiography, elektroretinografiya, kampimetriya, Ishikhar's test and FALANT, Rabkin's table. Etiotropny therapy of various forms of a blindness significantly differs and selected for each patient in an individual order.
The blindness is a heterogeneous group of diseases in ophthalmology which is characterized by decrease in visual acuity or color perception. This pathology is among the major medico-social problems as is the reason of an invalidization of patients. At the same time 3/4 cases of a blindness at timely diagnostics and treatment are reversible. According to the World Health Organization (WHO), about 100 million blind people, every year their number increase in the world. 90% of total number of blind patients live in developing countries and only 10% – in developed. Besides a cataract and glaucoma the leading role in developing of this pathology among inhabitants of the developing regions is occupied by the background, infectious and parasitic diseases which are giving in to treatment. In the developed countries the quantity of cases of a blindness against the background of age degenerate and dystrophic changes of a yellow spot and a diabetic retinopathy increases every year.
According to statistical WHO data, the most common cause of a blindness – a cataract (47,9%). Congenital options of a disease are caused by mutations. As a rule, the family form of a cataract, an aplaziya of an internal cover of an eyeball, tapetoretinalny degenerations, albinism are the reasons of decrease in visual acuity in such cases. A special type of this pathology – a kortikalny blindness at which clinical manifestations are caused by defeat of an occipital share of a brain. Widespread teratogena concerning an organ of vision – medicines, toxins and causative agents of infectious diseases.
There is a high risk of damage of eyes at action on a fruit of teratogenny factors at a stage of an embryonal development. In the pre-natal period development of a blindness is provoked by causative agents of a rubella, toxoplasmosis, flu, tuberculosis. At mature age the chlamydial origin of violations of sight against the background of trachoma is more often observed. Damage of eyes with frequent loss of sight is characteristic of such helminthoses as . Isolated cases of a blindness diagnose at a dirofilyarioza.
The etiology of a blindness of early age is connected with influence of triggers in the patrimonial or perinatal period. At the same time diagnose a retinopathy, a hypoplasia of visual ways or hypoxemic injury of an optical nerve which lead further to visual dysfunction for newborns. At children (especially premature) decrease in visual acuity is exponentiated by deficiency of vitamin A, a congenital cataract or a retinopathy. At patients of young age the majority of cases of a monocular blindness is caused by traumatic damages. In old age decrease in sight is connected both with the general diseases of an organism, and with the course of degenerate and dystrophic changes in a retina or an optic nerve.
Defeat of an internal cover of an eyeball or optical nerve with the progressing decrease in visual acuity is characteristic of such general diseases as arterial hypertension, atherosclerotic defeat of vessels, a retinopathy against the background of diabetes. The blindness can again arise against the background of pathologies of the central nervous system – meningitis, encephalitis, toxic damage of a brain. According to statistical data, at timely diagnostics the set of cases of this pathology is potentially reversible. As a rule, glaucoma in connection with development of an atrophy of an optic nerve becomes the reason of an irreversible blindness.
From the clinical point of view the blindness is classified on , scotoma, a gemianopsiya and daltonism. According to WHO data, the diagnosis a blindness can be established at ability to sight less than 3/60 or narrowing of the visual field to 10 degrees. If visual acuity is equal 0, it is about an absolute blindness. At the kept svetooshchushcheniye and response to change of its intensity, but impossibility to distinguish a form of surrounding objects, the blindness carries the name of subject. At civil option of visual dysfunction the patient cannot define the number of fingers on a hand at distance of 3 meters. Also allocate a professional blindness at which violations of sight interfere with performance of professional duties.
Specific symptom of a passing amavroz – sharp loss of sight lasting no more than 10 minutes. This phenomenon is connected with reversible ischemic changes in the pool of a carotid. Amavroz Lebera is shown nistagmy and the expressed decrease in visual acuity revealed at early children's age. Often this form of a blindness is combined with keratokonusy, a cataract, an astigmatism, a strabizm. Extra eye displays of pathology are presented by a delay of intellectual development, epileptic seizures, decrease in hearing, a hormonal imbalance, malformations of kidneys, bone system or TsNS. Patients with this option of a blindness are in rare instances capable to distinguish light from darkness or to monitor the movement of nearby objects.
At pathological scotomas defects of fields of vision which the patient sees as dark stains before eyes come to light. These defects are capable to close partially considered image. At detection of scotomas which the patient does not notice it is about "negative" option of the pathology caused by defeat of optical nervous fibers. Gemianopsiya is a binocular blindness with defeat of one of half of fields of vision. At a gomonimny form of a disease both right or left half, geteronimny binazalny – lateral, geteronimny bitemporal – medial departments of the visual field drop out. At daltonism ability to differentiation of a certain color is broken. Protanopiya is shown by inability to perception of red color, a tritanopiya – blue-violet, a deyteranopiya – green. Achromatopsia is the blindness which is characterized by pathological color perception at which patients are incapable to distinguish all shades of a color range.
Diagnosis of a blindness
Diagnosis of a blindness is based on carrying out a vizometriya, perimetry, an oftalmoskopiya, fluorescent angiography, elektroretinografiya, kampimetriya. Vizometriya allows to diagnose extent of violation of visual functions. To the I category carry patients with visual acuity 0,1-0,3 , to II – 0,05-0,1 , to III – 0,02-0,05 . At patients of the IV category the svetooshchushcheniye is kept – 0,02 , at V lack of a svetooshchushcheniye is noted. According to results of inspection of the patients entering in І and ІІ group carry to number of visually impaired. The diagnosis a blindness can be established only to persons III-V of groups. The visual field 5-10 ° according to perimetry corresponds ІІІ to category, less than 5 ° – IV.
Also when carrying out perimetry it is possible to reveal pathological scotomas which have an appearance of defects of a field of vision of an oval, rounded or arc-shaped shape. And in 4 slanting meridians measure by a kampimetriya method in temporal, nasal, frontal and podborodochny points the scotoma sizes with the subsequent fixing of indicators in the special card of the patient. The main method of diagnostics of a gemianopsiya – perimetry. At a gomonimny form of a blindness defects of fields of vision are found in temporal and nasal departments of different eyes. The Binazalny option of pathology is characterized by loss medial, and bitemporal – lateral half of the visual field.
At a passing amavroz carrying out a fluorescent angiography for the purpose of definition of exact localization of a zone of ischemia is shown. As a rule, the research allows to reveal an embolism of arteries of an internal cover of an eyeball. For Leber's amavroz decrease in amplitude of waves or their total absence when carrying out an elektroretinografiya is peculiar. At an oftalmoskopiya at patients 8 years on the periphery of an eye bottom are more senior kaltsifikata and pigmentary little bodies are defined. Apply Ishikhar's test, polychromatic tables of Rabkin, FALANT test to diagnosis of a color blindness.
Treatment of a blindness
At a passing amavroz in an urgentny order it is necessary to appoint vasodilating means, anticoagulants of direct action, a trombolitika, antiagregant. Specific tactics of treatment of a blindness Lebera is not developed. Symptomatic therapy includes reception of polyvitaminic complexes and carrying out intra orbital injections of vazodilatator, correction of visual acuity by means of points. At diagnosis of scotomas etiotropny treatment is required. If the otsloyka of a retina is a cause of illness, the vitrektomiya with the subsequent carrying out sealing or a ballonirovaniye skler is shown. At emergence of defects of a field of vision because of pathological new growths their removal is made. At the blindness caused by a brain angiospasm it is necessary to appoint spazmolitichesky means.
Etiotropny therapy of a gemianopsiya is based on knocking over of causal factors. Neurosurgical intervention at patients with this form of a blindness is shown at a craniocereberal injury, good-quality or malignant new growths of a brain. If special methods of treatment are inaccessible, the rehabilitation course is recommended. Specific tactics of therapy of a color blindness is not developed. Points with special filters or contact lenses are applied to correction of visual functions.
Forecast and prevention of a blindness
Specific prevention of a blindness is not developed. At timely diagnostics and treatment in most cases it is possible to keep visual functions. All patients with this pathology have to stay on the registry at the ophthalmologist. The forecast at a blindness is more often adverse. 95% of patients with amavrozy Lebera are irreversible lose sight at the age of 10 years or earlier. However at daltonism visual acuity often does not change. Decrease in visual functions can be the cause of temporary or permanent loss of working capacity. If it is impossible to restore functions of an organ of vision, appropriate to patients group of disability. At visual acuity 0,05-0,2 training at special school for visually impaired children, lower than 0,05 – in educational institutions for blind people is recommended.