ENTOPTICHESKY PHENOMENA

From Big Medical Encyclopedia

ENTOPTYChESKIE Ya of V L Yo of N of I Ya

(Greek entos inside + optikos relating to sight; a synonym entoptiche-sky phenomena) — subjective visual feelings moving or fixed light and hulls (figures), noted investigated in own eye and the eyes caused by features of an anatomic structure or its pathological changes.

Version E. I. the photopsia is (see) — feeling of light in eyes in the form of sparks, flashes, rings, spots, fiery surfaces, zigzags, etc., the arising at inadequate stimulation neyrore-tseptorny or carrying out and central departments of the visual analyzer.

Emergence of a row E. I. it is caused by features of a structure of a retina, napr, double light refraction in radial fibers of a retina in the field of the central pole — a fo-veola (Gaydinger's phenomenon, a phenomenon of «Gaydinger's brushes»), distribution of light along fibers of a retina of paramacular area (a phenomenon of «blue arches»), existence of a pigment in a macula lutea of a retina (a phenomenon of «Maxwell's spot»).

Gaydinger's (W. R. Hai-dinger) phenomenon is that at illumination of an eye the polarized light in a midfield of sight there are two triangles (or contrast dark a bunch, two brushes) connected by tops. Gaydinger's phenomenon is absent at persons with patol. changes in macular area of a retina (see), napr, at hemorrhages, dystrophy of a retina (see Retinopathies), etc.

The phenomenon of «blue arches» is shown in the form of bluish arc-shaped strips around a light source; it is observed in the darkened room at a view of a point source of light, preferably red color; has no clinical value.

The phenomenon of «Maxwell's spot» arises at a view of brightly lit screen after preliminary examining of the same screen during 15 — 20 sec. via the blue filter. The phenomenon is absent at changes in area of a macula lutea of a retina (see Retinopathies), retrobulbar neuritis (see. Optic nerve, pathology).

A considerable part of the entoptichesky phenomena is connected with blood circulation in vessels of a retina. Observation of the retinal vessels at transscleral raying of an eye, napr, by means of the lighter of a slit lamp or a diafanoskop, received the name of an autooftalmoskopiya, and the visible picture was called a figure of a retinal tree Pur-kinye (see Amotio of a retina). The macula lutea at the same time is perceived as an oval avascular zone with existence of the punctulate granularity called by macular «shagreen leather». At observation of brightly lit blue field it is possible to see uniform elements of blood in the form of the flashing bright points.

The mechanical irritation of a retina, napr, during the pressing by a glass rod or a finger on a sclera, causes a light feeling in the form of a spot on the party opposite to pressure — mechanophosphene: (see Amotio of a retina). It arises only at safety of neuroceptors of a retina and conduction paths. Lack of mechano-phosphene specifies on patol. changes of these structures of the visual analyzer.

Some E. I. inspections of the ophthalmologic patient can be used for a wedge. E.g., emergence of iridescent circles around a light source is characteristic of a bad attack of glaucoma (see); row E. I. use at early diagnosis of amotio of a retina. Artificially caused separate E. I. help with diagnosis of pathology of a retina and optic nerve at the complicated oftalmoskopiya at patients with opacification of optical environments, napr, at a cataract (see), the expressed miosis. Can point partial lack of mechanophosphene or an autooftalmoskopichesky picture of a retinal tree of Purkinye to amotio of a retina, narrowing of a field of vision at a glaukomatozny atrophy of an optic nerve.

The research of such entoptichesky phenomena as an autooftalmoskopiya, Gaydinger's phenomenon, observation of uniform elements of blood in brightly lit blue field give the chance to predict safety of the central sight at a cataract and opacification of a cornea (see).

Bibliography: Kravkov S. V. Eye

and its work, Psychophysiology of sight, hygiene of lighting, M., 1932; Adler’s physiology of the eye, ed. by R. A. Moses, St Louis, 1981. H. H. Pivovarov.

Яндекс.Метрика