ASTHENOPIA (Greek asthenes weak + ops, öpos of eyes) — quickly coming exhaustion of eyes during visual work (visual discomfort), especially at a short distance. Most often two types A meet. — akkomodativny and muscular (it is more correct And., caused by defects in binocular visual system). It is less often observed color And., the essence a cut consists what during the examining during nek-ry time of two different color tones begins to seem that they are identical.
At the heart of akkomodativny And. the exhaustion of a tsiliarny muscle connected with its excessive tension at a hypermetropia and a presbyopy, uneven reduction at an astigmatism, with its inborn or acquired weakness lies. In the latter case And. can arise also at an emmetropia. Weakening of a tsiliarny muscle is promoted by some general diseases of an organism. Phenomena akkomodativny And. are expressed that contours of letters and other small fixed objects become not clear, indistinct, there is pressure sense in eyes, dull ache about eyes and in a forehead, sometimes a sharp headache. For the prevention and elimination of the phenomena akkomodativny And. are necessary: timely optical correction of a hypermetropia (see. Far-sightedness ), presbyopies (see) and an astigmatism (see. Astigmatism of an eye ), respect for standards of hygiene of sight during the work at a short distance; the correct alternation of work and rest for eyes; fortifying treatment.
At muscular And. patients show complaints to bystry exhaustion of eyes, eye and head pains, passing diplopia (see) during the visual work at a short distance. These phenomena quickly are eliminated if to cover one eye. Reasons muscular And. there can be a myopia, a heterophoria, weakness of convergence, insufficiency of fusional reserves (see. the Associated movements of eyes ). Quite often these reasons are combined. At a nekorrigirovanny myopia as a result of dissociation between accommodation, edges it is almost not necessary, and the strengthened convergence weakness, bystry exhaustion of internal direct muscles appears. At a heterophoria and the weakened fusional ability of the phenomenon And. arise owing to a neuromuscular overstrain, a cut it is required to overcome a tendency to a deviation of one of eyes. If not to take timely measures, then can develop squint (see). These measures consist in the following: perhaps earlier optical correction of a myopia (see. Short-sightedness ), creation of favorable hygienic conditions for visual work, exercise on development of convergence and normal amplitude of a fuziya, at high degrees heterophorias (see) — glasses wearing with prisms.
Bibliography: The multivolume guide to eye diseases, under the editorship of V. N. Arkhangelsky, t. 1, book 1, page 282, M. 1962; Sachsenweger R. Pathologie und Klinik der Refraktionsanomalien, in book: Augenarzt, hrsg. v. K. Velhagen, Bd 2, S. 713, Lpz., 1972.
AA. C. Avetisov.