FIELD OF THE LOOK

From Big Medical Encyclopedia

FIELD OF THE LOOK — set of all points of space which an eye at the movements and the fixed position of the head can apprehend. Such space for one eye is called the monocular field of a look, for both eyes — the binocular field of a look. The item of century is defined by the volume of movements of eyes at their extreme assignment in different directions unlike fields of vision (see) — the space perceived by an eye at a motionless look and the fixed position of the head.

The research P. of century is conducted at suspicion of paresis or paralysis of muscles of an eyeglobe. The simplest method of a research P. of century consists in definition of provision of a cornea in relation to a palpebral fissure at extreme assignments of an eye and the motionless head. Normal at the movement of an eye of a knutra the inner edge of a cornea concerns the lacrimal meat, at the movements of a knaruzha the outer edge of a cornea reaches a lateral palpebral commissure. The volume of movements of eyes on a vertical (up and from top to bottom) define by comparison of mobility of both eyes. Quantitative delimitation of the field of a look is carried out by means of perimeter or Maddox's scale (see. Maddox stick, scale ), at the same time P.'s borders of century define in degrees. P.'s borders of century at various people considerably vary, they depend on a condition of muscles of an eyeglobe, and also on a structure of a facial skull, degree of a vystoyaniye of eyeglobes. By data I. I. Merkulova (1962), on average internal and outside borders make 45 — 50 °, upper — 40 °, lower — 50 °.

P.'s restriction with century more than on 5 ° in comparison with normal P. is considered century pathological. P.'s narrowing is observed at paresis or paralysis of muscles of an eyeglobe owing to the defeat of third cranial nerves or their kernels caused by a tumor of a brain, encephalitis, a cerebral stroke, etc. century. P.'s restriction with century happens on the party of action of the affected muscle. Depending on the nature of defeat of third cranial nerves P.'s restriction with century can be combined with diplopia (see), forced compensatory position of the head and other symptoms.

Binocular P.'s research of century helps to differentiate paresis and paralysis of muscles of an eyeglobe. At paralysis the simultaneous movement of eyes towards the affected muscle is impossible (see. Look paralysis, spasm ). At paresis perhaps simultaneous movement of eyes towards the affected muscle, at the same time eyeballs do not reach extreme assignments or are not capable is long to keep the provision of extreme assignment.


V. N. Marinchev.

Яндекс.Метрика