Central retinal dystrophy
Last reviewed: 23.04.2024
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Involutional macular degeneration of the retina (synonyms: age, senile, central chorioretinal dystrophy, age-related macular dystrophy, AMD) is the main cause of vision loss in people over 50 years old. This is a genetically determined disease with a primary localization of the pathological process in the pigment epithelium of the retina, the Bruch membrane and the chorio capillaries of the macular area.
Ophthalmoscopically, the following symptoms are distinguished: druses (nodular thickening of the basement membrane of the pigment epithelium of the retina), pigmentary (geographical) epithelial atrophy or hyperpigmentation, pigment epithelium, subretinal exudates (yellow exudative detachment), hemorrhages, fibrovascular scars, choroidal neovascular membrane, vitreous hemorrhage .
[Symptoms of central retinal dystrophy
Three main forms of dystrophy are distinguished by pathoanatomical signs: the dominant druses of the Bruch membrane, the nonexudative and exudative forms.
Clinical symptoms include a gradual decrease in central vision, metamorphosis, and central scotoma. Druses are an early clinical manifestation of the disease. Disturbances of visual functions appear with the development of macular degeneration. Visual acuity correlates with changes in local ERG, while the total ERG remains normal. The most often observed dry, or atrophic, form, which is characterized by atrophy of pigment epithelium. Rarely noted exudative, "wet" form, which is characterized by a rapid deterioration of visual acuity associated with the development of neovascular membranes, fibrovascular scars and hemorrhages in the retina and vitreous. The detachment of the pigment epithelium is often combined with the neovascular membrane and is a sign of the exudative form of age-related central degeneration of the retina.
The dominant druzy of the Bruch membrane is a bilateral disease with an autosomal dominant type of study that proceeds asymptomatically. Druses are located in the macular area peripapillyarno, rarely - on the periphery of the fundus. They have different shapes, size and color (from yellow to white), can be surrounded by a pigment.
On the PHAG, typical multiple focal regions of limited small-point late hyperfluorescence are noted. Until now, it remains unclear whether druses always precede age-related macular degeneration or may be an independent disease.
In non-exsudative form of central retinal dystrophy, druses are found in the macular area and various manifestations of the pathology of retinal pigment epithelium.
Geographic atrophy of the pigment epithelium is represented by separate large depigmented zones through which large choroidal vessels are visible, forming a horseshoe-shaped ring around the foveal region, where the xanthophilic pigment is preserved until the last stage. The risk of neovascular membrane formation is small. Geographic atrophy can develop against a background of medium and large drusen with fuzzy boundaries, disappearing, collapsing or peeling retinal pigment epithelium; the mineralization of drusen is noted, which in this case resemble brilliant bright yellow inclusions.
Non-geographic atrophy does not have clear boundaries, it looks like a small-dot hypopigmentation in combination with hyperpigmentation of pigment epithelium.
Focal hyperpigmentation can be an independent pathology or be combined with druses or adjacent areas of pigment epithelium atrophy and its detachment during neovascularization of the choroid (formation of the neovascular membrane). Pigment epithelial ruptures are a complication of retinal detachment and are caused by the emerging tension of the tissues.
The exudative form of macular degeneration associated with age is manifested by the exudative detachment of the sensory retina with subretinal hemorrhages and lipid exudation, dirty gray or yellow edema of the macula (cystoid macular edema), the formation of folds of the choroid, the detachment of the pigment epithelium, subretinal fibrosis. Subretinal exudate is usually opaque because of the high concentration of proteins, lipids, blood products, presence of fibrin. Thickening and serous detachment of the retinal pigment epithelium result from the formation of neovascularization under the pigment epithelium.
Choroidal neovascularization is the germination of blood vessels through the Bruch's membrane into the pigment epithelium. Blood and lipids and plasma leak through the neuro- and pigment epithelium. They stimulate fibrosis, which destroys the pigment epithelium and the outer layers of the retina. It is suggested that peroxide oxidation of lipids in the pigment epithelium is capable of inducing intraocular neovascularization due to the release of cytokines and other growth factors. The FAG helps in the diagnosis of choroidal neovascularization.
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Treatment of central retinal dystrophy
Treatment is aimed at slowing the pathological process. For this purpose, antioxidants are used primarily. Clinical observations show that the use of a- and b-carotene, cryptoxanthin, selenium and other drugs with antioxidant properties slows down the course of central chorioretinal dystrophy. Similarly, the action of vitamins E and C. Since zinc, which is involved in many enzymatic processes of protein and nucleic acid metabolism, is present in large numbers in the complex of retinal pigment epithelium-the choroid, suggest that the use of zinc-containing preparations should also slow the development of macular degeneration. A diet rich in fruits and vegetables is recommended.
To prevent destructive processes in the retina, it is necessary to use optical and pharmacological means of protection and prevention, so patients with macular degeneration associated with age, it is recommended to prescribe, in addition to antioxidants, vascular drugs and lipotropics, wearing sunglasses.
In the exudative form of the disease, laser photocoagulation is performed, guided by the results of FAG diagnostics.
Surgical methods remove choroidal neovascular membranes and subretinal hemorrhages. At present, operations are being developed for the transplantation of pigment epithelium and the photoreceptor layer of the retina. Positive results of photodynamic therapy were obtained in patients with subfoveal choroidal neovascularization. The disease is chronic, proceeds slowly and leads to a decrease in visual acuity.