Choroidal dystrophy

Dystrophic processes in the choroid can have a hereditary nature or a secondary nature, for example, be a consequence of the transferred inflammatory processes.

By localization, they can be generalized or focal, for example, located in the macular area of the retina. In case of dystrophy of the choroid, the retina is always involved in the pathological process, especially the pigment epithelium.

The pathogenesis of hereditary dystrophy of the choroid consists of genetically determined abiotrophy (absence of vascular layers) and secondary changes in photoreceptors and pigment epithelium.

The main ophthalmoscopic sign of this disease is atrophy of the choroid, accompanied by a change in the retinal pigment epithelium with the accumulation of pigment granules, and the presence of a metallic reflex. In the initial stage of atrophy of the chorio-capillary layer, large and medium vessels appear unchanged, but the dysfunction of the retina photoreceptors, caused by a disturbance in the nutrition of its outer layers, is already noted. As the process progresses, the vessels are sclerosed and acquire a yellowish white color. In the final stage of the disease, the retina and the choroid are atrophic, the vessels disappear and against the sclera there is only a small number of large choroid vessels. All signs of the dystrophic process are clearly visible in fluorescent angiography (PHAG).

Atrophy of the choroid is a common sign of many hereditary dystrophies of the retina and pigment epithelium.

There are various forms of generalized dystrophy of the choroid.

[1], [2], [3], [4], [5], [6], [7], [8]

Choroidderemia

Choroidderemia is a hereditary dystrophy of the choroid. This is a rare disease in males. Already in the early stages, along with signs of atrophy in the choroid, there are changes in the photoreceptors, mainly in rods on the middle periphery of the retina.

Type of inheritance linked to the X chromosome, gene locus on Xq21.

• All the daughters of the sick father are carriers. 50% of the sons of female carriers are sick. 50% of daughters of female carriers are also carriers.
• A sick father can not pass a gene to his sons.
• In female carriers - minimal changes, zones of peripheral atrophy and mottle in the RPE layer. Visual acuity, peripheral fields and Electroretinogram are normal.
• It is manifested by niktalopia in the first decade of life.

As the process progresses, night vision diminishes, concentric narrowing of the visual fields is revealed, ERG subnormal. Central vision persists until the late stage of the disease.

Ophthalmoscopically, in patients with men, a wide range of changes is revealed - from atrophy of chorio capillaries and minor changes in retinal pigment epithelium to complete absence of choroid and outer layers of the retina. In the first or second decade of life, changes are manifested in the appearance of a pathological reflex in ophthalmoscopy, the formation of coin-like foci of choroidal atrophy and retinal pigment epithelium, the accumulation of pigment in the form of phalanx or bone cells.

The diagnosis can be established on the basis of family history, the results of the examination of patients and their families, the study of ERG and the field of vision.

Symptoms (in order of manifestation)

• On the middle periphery - the areas of choroidal atrophy and atrophy of the RPE.
• Diffuse atrophy of chorio capillaries and RPE with preservation of medium and large vessels.
• Atrophies of medium and large choroidal vessels with exposure of the underlying sclera.

In comparison with the primary dystrophies of the retina, the fovea is preserved for a long time; The optic nerve disk and retinal vessels remain relatively normal.

• Electroretinogram. A scotopic electroretinogram is not recorded, the photopic - is abnormally subnormal.
• The electro-oculogram is subnormal.
• The phage of the middle stage of choroiddermia reveals the filling of the retinal vessels and large choroidal vessels, but not the chorio capillaries. Hypofluorescence corresponds to the intact fovea, the surrounding zone of hyperfluorescence - with "final" defects.

The prognosis is extremely unfavorable, but in most patients up to 6 decades of life vision is preserved, despite a sharp decrease in it.

[9], [10], [11], [12], [13]

Central areolar choroidal dystrophy

Type of inheritance is autosomal dominant, the gene locus is 17p. It manifests itself in the third decade of life by a gradual bilateral reduction of central vision.

Symptoms (in order of manifestation)

• Nonspecific granularity in the fovea.
• Delimited zones of RP atrophy and atrophy of the choriocapillary layer in the macula.
• Slowly expanding zone of "geographical" atrophy with visualization of large choroidal vessels.

Electroretinogram is normal. The electro-oculogram is normal.

The prognosis is unfavorable: low visual functions - to 6-7 decades of life.

[14], [15], [16]

Diffuse atrophy of the choroid

Type of inheritance is autosomal dominant. It manifests itself in 4-5 decades of life with a decrease in central vision or niktalopia.

Symptoms (in order of manifestation)

• Parapapillary and pericentral atrophy of RP and chorio capillaries.
• Gradual expansion of the zones until the entire fundus is involved.
• Atrophy of most large choroidal vessels and scleral translucence.
• Retinal vessels are of normal caliber or somewhat narrowed.
• Electroretinogram subnormal.

The prognosis is unfavorable because of early changes in the macula.

[17], [18], [19], [20], [21]

Helicoidal parapapillary chorioretinal degeneration

Type of inheritance is autosomal dominant. It appears in childhood.

Symptoms

• Two-sided, slowly expanding, in form resembling tongues, clearly defined bands of chorioretinal atrophy, starting from the optic nerve disc.
• Foci can be separate, peripheral, circular.
• Electroretinogram from normal to pathological.

The prognosis is different: the young can have a difficult course, in the elderly it is more favorable.

Pigmentary paravenous retinochoric atrophy

Pigmentary paravenous retinochoroid atrophy is a rare disease, usually detected by chance in young men. The type of inheritance is not known reliably, both types linked to the X chromosome and even linked to the Y chromosome are described.

Symptoms

• Two-sided deposition of the pigment in the form of "bony bodies" along the large retinal vessels.
• Adjacent delineated zones of chorioretinal atrophy, which may be located around the optic nerve disc.
• Electroretinogram, as a rule, is normal.

The prognosis is favorable, since changes in the macula are rare.