Blindness is a pathological condition in which the visual acuity is sharply reduced or completely absent. Depending on the form of the disease clinical symptomatology is a decrease in visual acuity, the appearance of livestock, color perception disorders, loss of the nasal or temporal halves of the visual field. Diagnosis of blindness is based on the results of visometry, perimetry, ophthalmoscopy, fluorescent angiography, electroretinography, campimetry, Ishihara and FALANT tests, Rabkin’s tables. Etiotropic therapy of different forms of blindness is significantly different and is selected for each patient individually.
Blindness is a heterogeneous group of diseases in ophthalmology, characterized by reduced visual acuity or color perception. This pathology is one of the most important medical and social problems, as it causes the disability of patients. In this case, 3 / 4 cases of blindness with timely diagnosis and treatment are reversible. According to the World Health Organization (WHO), there are about 100 million blind people in the world, their number increases every year. 90% of the total number of blind patients live in developing countries and only 10% – in developed countries. In addition to cataracts and glaucoma, the leading role in the emergence of this pathology among residents of developing regions are background, infectious and parasitic diseases that can be treated. In developed countries the number of blindness cases increases every year against the background of age-related degenerative-dystrophic changes of the yellow spot and diabetic retinopathy.
Reasons for blindness
According to WHO statistics, the most common cause of blindness is cataract (47.9%). Congenital variants of the disease are caused by mutations. As a rule, the causes of reduced visual acuity in such cases are the family form of lens opacity, aplasia of the inner eyeball, tapetoretinal degeneration, albinism. A special type of this pathology is cortical blindness, in which clinical manifestations are caused by lesions of the occipital lobe of the brain. Common teratogens in relation to the visual organ – drugs, toxins and pathogens of infectious diseases.
There is a high risk of eye damage if teratogenic factors act on the fetus during embryonic development. In the intrauterine period, the development of blindness is provoked by the agents of rubella, toxoplasmosis, influenza, tuberculosis. In adulthood, the chlamydia origin of vision disorders on the background of trachoma is more often observed. Eye damage with frequent loss of vision is typical for such helminths as onchocerciasis. Single cases of blindness are diagnosed with dirophilariasis.
The etiology of early blindness is associated with exposure to triggers during the birth or perinatal period. In this case, newborns are diagnosed with retinopathy, hypoplasia of the visual pathways or hypoxic damage to the optical nerve, which further leads to visual dysfunction. In children (especially premature infants) visual acuity reduction potentiates vitamin A deficiency, congenital lens opacity or retinopathy. In young patients, most cases of monocular blindness are due to traumatic injuries. In old age, vision loss is associated with both general diseases of the body, and with degenerative and dystrophic changes in the retina or optic nerve.
Affection of the inner shell of the eyeball or optic nerve with progressive reduction of visual acuity is typical for such general diseases as arterial hypertension, atherosclerotic vascular lesions, retinopathy against the background of diabetes. Blindness may occur again against the background of pathologies of the central nervous system – meningitis, encephalitis, toxic brain damage. According to statistics, at timely diagnosis, many cases of this pathology is potentially reversible. As a rule, the cause of irreversible blindness is glaucoma due to the development of atrophy of the optic nerve.