Stargardt disease characterized by a yellow-spotted fundus, called yellow-spotted dystrophy, is an anomaly of the retina zone. It originates from pigment epithelium and is expressed by deterioration of visual acuity from two sides in the 10-20 age group.
The disease was explained by K. Stargardt at the very beginning of the 20th century, as the macular zone disease, which is inherited.
It is characterized by an ophthalmoscopic picture with signs of polymorphism: "broken bronze", "bullish eye", dystrophy of the choroid, and so on.
Using the gene determination method, only on the basis of its location in the genome, the main locus of the gene called ABCR, which determines Stargardt's disease and was expressed in the light-responsive sensory neurons of the retina, was isolated. In the case of an autosomal dominant type of hereditary disease, the location of defective genes in chromosomes 13q and 6q14 is determined.
Symptomatics and diagnosis of Stargardt's disease
Results of a genetic study conducted recently suggest that, despite differences in the combination of disease manifestations, pigment retinitis, Stargardt disease, yellow-spotted fundus and molecular level destruction, depending on age, are provoked by allelic abnormalities of the ABCR locus.
Anomaly "bull's eye" is ophthalmoscopically determined by a dark spot in the center around which there is a wide ring of hypopigmentation - behind it, as a rule, is a ring of super pigmentation. On PHAG, in the case of a simple anomaly, in the background of a region without deviations, places without fluorescence or with hypofluorescence with prominent chorio capillaries are determined. From the point of view of the structure, it is characteristic to increase the proportion of the colorant in the center of the fundus, the atrophy of the adjacent retinal pigment tissue and the increase in pigment tissue. The deprivation of fluorescence in the macular zone is due to the accumulation in the pigment epithelium of the retina of lipofuscin, which is screened by fluorescein. At the same time, glycolipoprotein lipofuscin lowers the oxidative property of lysosomes and increases the pH of retinal pigment epithelial tissues, which leads to a loss of their membrane integrity.
Sometimes a rare variety of yellow-spotted dystrophy is diagnosed, without deviations in the macular zone. With this form of disease between the macula and the equator, a large number of spots of yellowish color of various forms are observed, the arrangement of which can be quite different - they can be combined or separate. Over time, color, shape and size can vary, the picture may change on the PHAG: zones with hyperfluorescence are transformed into zones with hypofluorescence, which indicates a decrease in retinal pigment tissue.
All Stargardt sufferers are diagnosed with partial or complete central scotomas of different sizes, the type of which depends on the passage of the process. In the case of yellow-spotted dystrophy, the visual field can have normal parameters provided there are no deviations in the macular zone.
Most of the patients have a color deviation in both deuteranopia and red-green dichromasia, but there may be more pronounced forms. In the case of a yellow-spotted anomaly, the color difference can be in order.
The contrast susceptibility of space in the case of Stargardt disease has large deviations in the entire frequency coverage with a considerable decrease in the mean place and absolute deprivation in the place of large wave values - the pattern of cone dysfunction. Contrast sensitivity in the center of the retina within 6-10 degrees is not observed.
At the initial stages of Stargardt's disease and the yellow-spot anomaly, the parameters for electroretinography and electrooculography are normal. In more complex stages, the cone components decrease on electroretinography, and on electrooculography they are slightly below the norm. Local electroretinography gives unsatisfactory results already in the early stages of the disease and goes into a non-fixed form during the course of the disease.
The method of diagnosis, excluding all factors not characteristic of the disease, should be performed with the prevailing developing anomaly of the retina of the retina in the center, cone, cone-rod and rod-cone anomaly, X-linked retinosis, vitelliform macular anomaly, obtained by medical abnormalities, in the case of acute intoxication during the period of bearing of the child.
Therapy of Stargardt disease
At the moment there is no available treatment for this genetic disease. Doctors advise using sun glasses to delay its progression. And that patients can see, it is recommended to use loops.