Blue (blue) sclera: causes, symptoms, diagnosis, treatment

Blue sclera can be a symptom of a number of systemic diseases.

"Blue sclera" is most often a sign of Lobstein-Van der Heve syndrome, which belongs to the group of constitutional defects of connective tissue, caused by multiple gene damages. The type of inheritance is autosomal dominant, with high (about 70%) pevetrance. It is rare - 1 case per 40-60 thousand newborns.

The key symptoms of blue sclera syndrome are: hearing loss, bilateral blue (sometimes blue) coloration of the sclera, and increased bone fragility. The most constant and most pronounced symptom is the blue-light blue coloration of the sclera, observed in 100% of patients with this syndrome. Blue sclera is caused by the fact that the pigment of the choroid shines through the thinned and especially transparent sclera. Studies have recorded thinning of the sclera, a decrease in the number of collagen and elastic fibers, metachromatic coloration of the main substance, indicating an increase in the content of mucopolysaccharides, which indicates the immaturity of fibrous tissue in blue sclera syndrome, and the persistence of embryonic sclera. There is an opinion that the blue-light blue color of the sclera is caused not by its thinning, but by increased transparency as a result of a change in the colloidal-chemical properties of the tissue. Based on this, the most accurate term for describing this pathological condition is proposed: “transparent sclera”.

Blue sclera in this syndrome are determined immediately after birth; they are more intense than in healthy newborns and do not disappear at all by the 5th-6th month, as usually happens. The size of the eyes, in most cases, is not changed. In addition to blue sclera, other eye anomalies may be observed: anterior embryotoxon, hypoplasia of the iris, zonular or cortical cataract, glaucoma, color blindness, corneal opacities, etc.

The second symptom of the "blue sclera" syndrome is bone fragility, which is combined with weakness of the ligament-articular apparatus, observed in approximately 65% of patients. This symptom can appear at different times, based on which 3 types of the disease are distinguished.

• The first type is the most severe lesion, in which fractures occur in utero, during labor, or shortly after birth. These children die in utero or in early childhood.
• In the second type of "blue sclera" syndrome, fractures occur in early childhood. The prognosis for life in such situations is favorable, although due to numerous fractures that occur unexpectedly or with little effort, dislocations and subluxations, disfiguring deformations of the skeleton remain.
• The third type is characterized by the occurrence of fractures at the age of 2-3 years; the number and danger of their occurrence decreases over time by the puberty period. The primary causes of bone fragility are considered to be extreme bone porosity, deficiency of calcareous compounds, the embryonic nature of the bone and other manifestations of its hypoplasia.

The third sign of the "blue sclera" syndrome is progressive hearing loss, which is a consequence of otosclerosis and underdevelopment of the labyrinth. Hearing loss develops in approximately half (45-50% of patients).

From time to time, the typical triad of "blue sclera" syndrome is combined with various anomalies of the mesodermal tissue, of which the most common are congenital heart defects, cleft palate, syndactyly and other anomalies.

Treatment of blue sclera syndrome is symptomatic.

Blue sclera may also be seen in patients suffering from Ehlers-Danlos syndrome, a disease with dominant and autosomal recessive inheritance. Ehlers-Danlos syndrome begins before the age of 3 and is characterized by increased elasticity of the skin, fragility and vulnerability of blood vessels, and weakness of the articular-ligamentous apparatus. These patients often have microcornea, keratoconus, subluxation of the lens, and retinal detachment. Weakness of the sclera sometimes leads to its rupture, including with minor injuries to the eyeball.

Blue sclera can also be a sign of Lowe's oculocerebrorenal syndrome, an autosomal recessive disorder that affects only boys. Patients have cataracts with microphthalmos from birth, and 75% of patients have elevated intraocular pressure.

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