SKOTOMETRIYA

From Big Medical Encyclopedia

SKOTOMETRIYA (Greek skotos darkness + metreo to measure, measure) — identification and measurement of focal defects of a field of vision (scotomas). The page is a valuable method of a research fields of vision (see), supplementing to a perimetrium (see); it is applied to early diagnosis of the eye and neurologic diseases which are followed by emergence cattle (see): dystrophic changes retinas (see), glaucomas (see), neuritis and atrophy optic nerve (see), tumors of a brain, etc. S. allows to watch a current patol. process and to control efficiency of treatment.

Fig. 1. The Skotometrichesky scheme of Byerrum — Samoylova: in the center of a circle a point of fixing of a look; 1 and 2 — area of a blind spot at a research according to right and the left eye.
Fig. 2. Projective kampimetr Auto-Plot: 1 — the projective device; 2 — a support for a chin; 3 — the plastic screen; 4 — a point of fixing of a look; 5 — a pantograph; 6 — the skotometrichesky scheme.
Fig. 3. The Skotometrichesky scheme for registration of the scotomas revealed by means of a kampimetr of Auto-Plot: the point of fixing of a look is designated by a cross; 1 and 2 — area of a blind spot at a research according to right and the left eye.

Depending on size and localization of scotomas under review apply various ways C. The devices used to S. call skotometram. For identification and measurement of the central, pericentral and paracentral scotomas use more often kampimetriya (see) — a research of a field of vision on a plane surface (kampimetra). By means of the special device — a kampimetrichesky pantograph 10-multiply reduced image of scotoma is transferred from a kampimetr to the skotometrichesky tangential scheme of Byerrum — Samoylova (fig. 1), allowing to express the sizes of scotoma in degrees. This scheme is especially convenient for registration of the scotomas connected with a blind spot and angioscotomas. In the USA Lloyd is applied to detection of the above-stated scotomas kampimetr (skotometr), modified by J. N. Evans; at the same time for registration of scotomas use rectangular system of coordinates — the skotometrichesky scheme of Lloyd — Evans. This scheme is convenient for fixing of the central scotoma, but gives distortion of a configuration of pericentral defects of a field of vision. The most perfect is Auto-Plot (fig. 2) which is released abroad projective kampimetr (skotometr), in Krom the image of a white or color test object to dia. 0,5 — 10 mm receive on the white opaque screen by means of a projector, and registration of defects of a field of vision is carried out semi-automatic by means of a pantograph on the special skotometrichesky scheme (fig. 3). Simplicity of carrying out a research and opportunity by the patient to find and register at itself scotoma belongs to advantages of this device.

For exact establishment of a form and the sizes of the central scotoma, at a cut exact central fixing of a look is complicated by a sore eye, it is possible to use stereoscopic kampimetrichesky devices, napr, skotometr Heyttsa. At the same time exact fixing of a look is reached at the expense of a healthy eye. As use of a stereoscope demands carrying out a research at small distance from an eye (30 — 35 cm), use test objects no more than 1 — 2 mm in size. These mobile objects can be white (for detection of absolute central scotoma) or color (for detection of the central scotoma for the colors).

Applied earlier to detection of small central scotomas skotometr Birkh-Girshfelda in modern a wedge, practice it is not used.

Fig. 4. The diagrammatic representation of a plate for test of nine points (circles can be black or color).

Easy way of detection of the scotomas and microscotomas located in the central part of a field of vision is, offered by V. P. Odintsov and modified by V. N. Marinchev, the test of nine points. The research is conducted by means of a white plate (fig. 4), are applied on a cut 9 black or color (red, green, yellow or blue) the circles located in 3 rows on 3 circles in everyone. Diameter of circles 2 — 3 mm, distance between them 2 — 5 mm. To the patient suggest to record a look on the central circle of the plate located at distance of 33 — 35 cm from an eye and to define whether he sees other eight. Then the research is repeated, changing a point of fixing of a look (the patient consistently fixes a look on other 8 circles). Thus investigate all central part of a field of vision. Normal investigated during the fixing of a look on one of circles shall see all others; in the presence of microscotoma or scotoma one or several circles drop out of zero sight. The research conducted with color circles allows to reveal scotoma for the colors.


V. N. Marinchev.

Яндекс.Метрика