Absolute or medical blindness is a total loss of vision, an inability to distinguish light from darkness. In this condition, the vision is 0. A distinction is also made between civil (or practical, domestic) blindness, which loses the ability to navigate in the environment, to move around the house without assistance, but retains the perception of light and even the ability to distinguish the contours of large objects. The category of practically blind people include persons with visual acuity from light perception to 0.04 on the best eye with the transferable correction by conventional means. Such vision is called residual. It should be noted that in different countries the criteria for determining civil blindness is different. Residual vision contributes to the development of some spatial representations, but it is not enough to use it for work that requires constant visual control. Therefore, education and training of the almost blind, as well as persons with absolute blindness, is carried out without the participation of their visual system.
Weak-sighted people are those whose visual acuity of the best eye with the usual optical correction is 0.05-0.2. This allows such persons in especially favorable conditions to use their vision for training and other work that does not require high visual acuity. Telescopic glasses, magnifying glasses and other special means of vision correction significantly facilitate the visual work of visually impaired people and increase their performance.
Universal 9-year training has been introduced for them and a network of special schools has been launched. An ophthalmologist serving a school for the blind and visually impaired has a major role in implementing a system of measures to protect the visually impaired and residual vision of students. The ophthalmologist takes part in equipping schools for the blind and visually impaired children, systematically conducts an in-depth examination of the eyesight of all students in these schools, provides them with necessary treatment, strives to create optimal hygienic conditions in schools for the blind and visually impaired children, and advises teachers of schools on all these issues.
When recruiting special schools, the instruction on admission of children to schools for the blind and visually impaired should be followed. It is necessary to carefully check the vision examination card filled out before sending a child to a school for the blind and visually impaired to make sure that this examination was carried out correctly and fully enough. In the first days of the school year, an ophthalmologist, together with nurses and teachers should correctly place students in the classroom according to their state of vision and height. Twice a year in-depth examinations of children’s eyesight should be conducted. The results of the examination, as well as detailed recommendations of the doctor regarding the mode of training and visual work, treatment, optical means of vision correction, consultations with other specialists, physical training are recorded in the medical records.
Children with progressive diseases of the visual organ (glaucoma, incomplete atrophy of the optic nerve, traumatic cataract, pigmented degeneration of the retina, inflammatory diseases of the cornea, complicated myopia, detached retina, etc.) and the condition of the eyes (some forms of congenital and secondary cataract, amblyopia, etc.), where it is possible to improve vision with active, highly qualified treatment, deserve special attention.
A lot of work to attract the blind to socially useful work and to improve their cultural level is done by societies of the blind. Members of the society accept persons from the age of 14 with visual acuity in the best eye up to 0.08 (with correction), as well as in case of sharp narrowing of the visual field.
Continuously increasing welfare of the population, increasing material and cultural level, widely conducted preventive measures and development of specialized eye care contribute to further reduction of the number of blind and visually impaired.