Amaurosis Leber: causes, symptoms, diagnosis, treatment

Congenital amaurosis of Leber is the most severe manifestation of retinitis pigmentosa (generalized form), observed from birth; - a very rare and serious disease with systemic manifestations.

[1], [2], [3], [4]

What causes Leber's amaurosis?

The cause of the disease is the absence of differentiation of pigment epithelial cells and photoreceptors.

Often there is an autosomal recessive type of transmission of the disease, and it was recently associated with two different genes, including the mutation of the gene of rhodopsin. Currently, Leber's amaurosis is viewed as a heterogeneous group of disorders in which sticks and cones are affected.

Symptoms of amaurosis Leber

The main symptoms are: absence of central vision, unregistered or abnormal subnormal ERG, nystagmus. Diagnosis of congenital amaurosis of Leber is very difficult, because the symptoms found in patients: strabismus, keratoconus, high grade hypermetropia, neurological and neuromuscular disorders, hearing loss, mental retardation, may be in other systemic diseases. It is manifested by blindness at birth or in the first few months of life. Vision in many children improves with a brighter light.

In this disease, children are either born blind or lose sight at the age of about 10 years. During the first 3-4 months of life, most parents note that they lack the fixation of objects and reactions to light, the typical eye symptoms characteristic of children born blind: wandering eyes and nystagmus, which are noted in the first months of life. In infants, the fundus may look normal, but with time, pathological changes necessarily appear. Eye symptoms include various pigment changes in the posterior pole of the eye from hyperpigmented to non-pigmented foci of the salt and pepper type, pigment migration in the retina and pigment accumulations, atrophy of pigment epithelium and capillaries of the choroid, less often multiple unevenly yellowish-white spots on the periphery and middle periphery retina. Pigmented deposits in the form of bony bodies at the periphery of the fundus are found in almost all patients with Leber's amaurosis at the age of 8-10 years, but these deposits can be very small, resembling a rash with rubella. The disc of the optic nerve, as a rule, is pale, the vessels of the retina narrowed. Changes in the fundus usually progress, but unlike typical retinitis pigmentosa, functional changes (visual acuity, field of vision, ERG) usually remain the same as in the initial examination. With time, after 15 years, in patients with Leber's amaurosis, keratoconus can develop.

Diagnosis of amaurosis Leber

In a microscopic examination, subretinal inclusions, consisting of the rejected outer segments of photoreceptors and macrophages, are identified in areas corresponding to ophthalmically visible white spots. External segments of rods are absent, a small number of modified cones is retained, other cellular elements are undifferentiated photoreceptors and embryonic cells of pigment epithelium.

Differential diagnosis is performed with a dominant atrophy of the optic nerve, in which the prognosis for vision is much better, as well as with similar changes for rubella and congenital syphilis.

The main symptom of Leber's congenital amaurosis, on which differential diagnosis is based, is either an unregistered or abnormal subnormal ERG, while with ERG atrophy, syphilis and rubella ERG is either normal or subnormal. With congenital amaurosis Leber, various common neurological and neurodegenerative disorders are possible, cerebral atrophy, mental retardation, kidney disease are noted. However, the intellectual development of children with congenital amaurosis of Leber can be normal.

Diagnostic criteria for amaurosis Leber:

• Pupillary reflexes are flaccid or absent.
• Changes in the fundus may not be, despite the low visual acuity.
• The most common symptom is the areas of peripheral chorioretinal atrophy and redistribution of the pigment.
• Other symptoms: edema of the optic nerve disk, changes in the type of "salt with pepper", diffuse white spots, macular macular and maculopathy by the type of "bovine eye."
• Pallor of the optic nerve disk and a decrease in the caliber of arterioles appear simultaneously with ophthalmoscopic manifestations.

Other ophthalmic symptoms:

• Hypermetria, keratoconus and keratoglobus.
• Cataract can occur in the 2nd decade of life.
• Nystagmus, wandering eye movements, strabismus.
• A characteristic symptom is oculopalgic syndrome, in which frequent rubbing of eyeballs leads to enophthalmus and resorption of orbital adipose tissue.

Electroretinogram, as a rule, is not recorded even in the early stages with a normal fundus.

The forecast is extremely unfavorable. May be accompanied by mental retardation, deafness, epilepsy, CNS and kidney anomalies, congenital malformation of the skeleton and endocrine dysfunction.

[5], [6], [7], [8]