BIOMICROSCOPY OF A EYE

From Big Medical Encyclopedia

BIOMICROSCOPY OF A EYE (grech, bios life + mikros small + skopeo to observe, investigate) — the special method of a research giving the chance in details to examine the optical refracting environments and fabrics of an eyeglobe.

B. it is for the first time offered by A. Gullstrand in 1911. The phenomenon of light contrast (Tyndall's phenomenon) is the cornerstone of a method.

By means of B. it is possible to find the smallest changes in an eye caused by a disease or an injury, to diagnose very small foreign bodys. The method is of great value in diagnosis of a number of diseases of eyes (e.g., trachomas, glaucomas, cataracts, new growths of an organ of sight, etc.).

The research is made by means of the special device — slit lamp (see). The domestic slit lamp of ShL-56 combines the powerful lighter (500 thousand luxury) and the binocular stereomicroscope with resolving power from X5 to X60. A microscope have directly before the studied fabric, the lighter — sideways. The corner between them is called a corner of biomicroscopy. It varies within +60 °. The research is conducted in the dark room. Sharp contrast of the sites of an eye darkened and lit with a lamp allows to see details, indiscernible at usual lighting.

In the course of B. the next ways of lighting are applied: a direct focal, parafocal, ostsillyatorny, transmitted light, the sliding beam, the mirror field. Using special devices, it is possible to examine in infrared and ultraviolet rays of a range, the luminescent, polarized light.

Fig. 1. Optical section of a cornea: and, in — a front surface; d, e, z — a back surface; — e and — z — thickness of a cornea. Fig. 2. Türk's line at biomicroscopy (whitish points): at the left — in a transmitted light; on the right — in optical section of a cornea.

The research in direct focal lighting allows to receive the optical section (optical section) of a cornea, crystalline lens, vitreous, a retina and optic disk. Optical section of a cornea has an appearance of slightly grayish, opalescent prism (fig. 1), width a cut depends on width of a bunch of a transmitted light. Normal the section is speckled by gray points and strokes — the fibrilla cut by a beam of light and nerves of a cornea so look. In the presence in a cornea of inflammatory focus or opacification optical section gives the chance to resolve an issue of that, the pathological center as fabric of a cornea is deeply struck is located where exactly. In case of existence of a foreign body survey in optical section helps to establish where it is — in a cornea or gets into a cavity of an eye that correctly orients the doctor in the choice of a method of intervention.

At B. Türk's line easily comes to light, edges occurs in 50% of cases at a research of healthy eyes, generally at children. Türk's line is changeable, its education and a characteristic arrangement connect with thermal current of intraocular liquid. Cooling of the liquid moving along a back surface of a cornea and delay thereof leads speeds of its current to sedimentation on a cornea of the cellular elements weighed in chamber moisture. The line is located on a back surface of a cornea, vertically below, and reaches the level of the bottom pupillary edge. It consists of leukocytes and lymphocytes which number fluctuates from 10 to 30. In a transmitted light cellular elements have an appearance of translucent deposits, in direct focal light take a form of whitish points (fig. 2).

Fig. 3. Optical section of a crystalline lens (an explanation in the text).

During the focusing of light and a microscope on a crystalline lens (direct focal light) optical section of a crystalline lens in the form of a biconvex transparent body is found (see. Crystalline lens ). In a section grayish oval strips — the zones of the section caused by various density of substance of a crystalline lens (fig. 3) are visible. Inner surfaces of an embryonal kernel (1) with the embryonal seams designated in the drawing by black Y-shaped lines, an outer surface of an embryonal kernel (2), a surface of a senile kernel (3), cortical substance (4), zones of splitting (5), front and back surfaces of a crystalline lens (6) are allocated. Studying of optical section of a crystalline lens gives the chance to see and to precisely localize gentle initial opacifications of its substance that is of great importance in any early diagnosis of cataracts.

By means of a method of biomicroscopy of a vitreous reveal in it fibrillar structures of gray color (a skeleton of a vitreous), indiscernible at a research by other methods. Studying of these structures has a certain diagnostic value, especially at short-sightedness.

Biomicroscopy of an eyeground (bio-mikrooftalmoskopiya), biomicroscopy of fabrics of an eyeground in beams of a range (biomikrokhromooftalmoskopiya) open new opportunities in oftalmoskopichesky diagnosis (see. Oftalmoskopiya ). Use of direct focal light allows to see the optical section of a retina and an optic disk. The retina comes to light in the form of the concave-convex translucent grayish strip located between a vitreous and an idiovascular cover of an eye. The research of optical section of a mesh cover helps to diagnose and to precisely localize small hemorrhages, microaneurysms of vessels, elements of dystrophy of fabric.

The optic disk at bio-microscopy thanks to transparency of the nerve fibrils creating it is looked through to a trellised plate of a sclera. Survey of an optic disk helps early differential diagnosis of an optic neuritis and a congestive nipple. A little smaller opportunities open at biomicroscopy of opaque departments of an eyeglobe, in particular conjunctivas, an iris of the eye, an idiovascular cover. However and in this case the method B. of is important addition of other methods of inspection of the patient with a disease of eyes.

See also Inspection of the patient (ophthalmologic).


Bibliography: Koreyevich I. A. Biomikroskopiya of an eye, Kiev, 1969; Sh at l of a ý-pin of N. B. Biomikroskopiya of an eye, M., 1974; Berliner M. L. Biomicroscopy of the eye, v. 1—2, N. Y., 1949, bibliogr.; Kajiura M., Hashimoto H. T a k a h a s h i F. Recent advances in biomicroscopy of the fundus, Eye, Ear, Nose Tlir. Monthly, v. 53, p. 17, 1974.

H. B. Shulpina.

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