Chorioretinal dystrophy

Description:

It (a senile makulodistrofiya, the central disiiformny dystrophy like Kunt — Yuniusa, etc.) — represents bilateral chronic dystrophic process with preferential defeat of a choriocapillary layer of a horioidea, vitreous membrane of Bruch (a boundary plate between a retina and horioidey) and a layer of a pigmental epithelium of a retina. Prevalence in the general population increases with age: 1,6% at the age of 51 — 64 years, 11% at the age of 65 — 74 and 27,9% at persons are more senior than 75 years, meets at women more often; is the main reason for irreversible loss of the central sight in an after-life.

Symptoms of Chorioretinal dystrophy:

At not exudative form at first there are no complaints either, or metamorphopsias (a curvature of straight lines) can be noted, visual acuity long remains not changed; then the central scotoma (i.e. the site of loss of a field of vision in its borders) because of an atrophy of a choriocapillary layer and a pigmental epithelium which is shown some "stushevannost" of objects in a sight midfield develops; sharpness of the central sight considerably goes down. Objectively at an oftalmoskopiya under a retina of macular and paramacular area the multiple small, roundish or oval, slightly acting ochazhka of white or yellow color sometimes bordered with a pigmental rim, places merging in the yellow-white conglomerates divided by brown glybka of a pigment are visible. Process can be stabilized. On a pair eye the TsHRD exudative form can develop.
The TsHRD exudative form passes 5 stages in the development: 1) the stage of exudative amotio of a pigmental epithelium — sharpness of the central sight remains high (0,8 — 1,0), the passing weak hypermetropia or an astigmatism is possible; in certain cases there are complaints to a curvature, sinuosity of straight lines, feeling of a look "through a sheet of water" (metamorphopsias), a translucent single spot or group of dark stains before an eye (relative positive scotoma), flashes of light (photopsia). The retina in the field of a macula lutea is slightly raised in a vitreous in the form of a dome with clear yellowish boundary, druses become invisible; perhaps independent prileganiye of amotio; 2) a stage of exudative amotio of a neuroepithelium — sight is reduced more, the same other complaints, however clearness of borders of amotio decreases, the raised retina is edematous; 3) a neovascularization stage — sharp decrease in visual acuity to 0,1 — 0,2 or to the 100-th, loss of ability to read and write; oftalmoskopichesk the area of a retina in the field of a macula lutea gains dirty-gray color, clustery hypostasis of a neuroepithelium and hemorrhage under a retina or in a vitreous develops; research PHAGE fixes fluorescence of neogenic vessels (a subretinal neovascular membrane) in the form of "lace"; 4) the stage of exudative and hemorrhagic amotio pigmental and a neuroepithelium — sight remains low, in macular area the discal center by the size to several diameters of an optic disk of white-pink or gray-brown color with deposits of a pigment and neogenic vessels kistevidno regenerated by a retina with a clear boundary and a prominention in a vitreous was created; 5) the cicatricial stage is characterized by development of fibrous fabric.
The diagnosis is established on the basis of characteristic complaints of the patient (a curvature of straight lines and other types of metamorphopsias), by researches of visual functions (sharpness of the central sight, a kampimetriya, the test of "nine points" or Amsler's grid), oftalmoskopiya, a fluorescent angiography of an eyeground.
Sometimes carrying out the differential diagnosis with a horioidea melanosarcoma is required.
The disease is usually shown after 60 years, at first in one eye, and approximately in 4 years similar changes in a pair eye develop. A clinical current chronic, slowly progressing. Disease severity is defined by bilateral defeat, the central localization of process on an eyeground and serious decline in quality of life because of loss of an opportunity to read and write.

Reasons of Chorioretinal dystrophy:

The etiology is unknown though the family, hereditary nature of process with an autosomal and dominant mode of inheritance is established. Risk factors are atherosclerosis and the ultra-violet radiation leading to accumulation of toxic products of metabolism (free radicals) in an epithelium of a retina and formation of colloid druses.
The central chorioretinal dystrophy (TsHRD) can be carried to amyloidoses of a back segment of an eye: dystrophic process begins with emergence of accumulations of solid or soft colloid substance (so-called druses) between Bruch's membrane and a pigmental epithelium of a retina in the field of a macula lutea and in a paramacular zone. The pigmental epithelium in places of contact with solid colloid substance becomes thinner, loses a pigment, and in the neighboring sites there is its thickening and a hyperplasia. Bruch's membrane of uneven thickness with calcification of its elastic and collagenic fibers, and in a choriocapillary layer of the subject horioidea occurs a thickening and hyalinization of a stroma (not exudative, atrophic or the TsHRD dry form). "Soft" druses can cause exudative amotio of a pigmental epithelium, and then and a retina neuroepithelium (exudative or the TsHRD distsiformny form). Further development of process at this option of pathology is followed by development under a membrane retina from neogenic vessels and transition of a disease to an exudative and hemorrhagic stage with the advent of hemorrhages under a pigmental epithelium, in subretinal space or (seldom) in a vitreous. In the subsequent there comes the resorption of a hemorrhage and development of fibrous cicatricial fabric.
On a pathogeny distinguish the TsHRD following forms: not exudative (dry, atrophic) — 10 — 15% of cases and exudative (distsiformny) — 85 — 90% of cases. Stages of a clinical current of exudative TsHRD distinguish depending on type of the exfoliated retina epithelium (pigmental or a neuroepithelium) and character of subepithelial contents (exudate, a neovascular membrane, blood, fibrous fabric) — see in more detail in the description of symptomatology.

Treatment of Chorioretinal dystrophy:

Treatment can be medicamentous, laser and, more rare, surgical. It is directed to stabilization and compensation of process as the complete recovery of normal sight is impossible. At an atrophic not exudative form dezagregant, vasoprotectives, antioxidants and vasodilating drugs (Cavintonum) appoint 2 courses a year — (in the spring and in the fall), carry out stimulation of a retina by an out-of-focus beam of the geliyneonovy laser. At exudative distsiformny TsHRD local and general dehydrational therapy, laser coagulation of a retina and subretinal neovascular membranes preferably krypton laser is appointed. Surgical methods of treatment are directed or to improvement of blood supply of a back segment of an eye (revascularization, a vazorekonstruktion at not exudative form), or to removal of subretinal neovascular membranes. If the makulodistrofiya is combined with a cataract, removal of a muddy crystalline lens is carried out by the known technique, but instead of a usual artificial crystalline lens it is possible to implant special intraocular lenses which displace the image on not affected area of a retina (sferoprizmatichesky lenses) or give the enlarged image on a retina (bifocal lenses).
The critical visual acuity favorable for treatment — 0,2 and above. In general the forecast concerning sight adverse.