Anomalies of corneal development: causes, symptoms, diagnosis, treatment

Anomalies of the development of the cornea are expressed by a change in its size and shape.

Megalocornea - a giant cornea (diameter more than 11 mm) - is sometimes a family-hereditary anomaly. In this case, there is no other pathology.

A large cornea can be not only congenital, but also acquired pathology. In this case, the cornea increases in size again in the presence of uncompensated glaucoma at a young age.

Microcornea - a small cornea (diameter 5-9 mm) - can be either a one-sided or two-sided anomaly. The eyeball in such cases is also reduced in size (microphthalmus), although cases of a small cornea in the eyes of normal size are noted. With an unusually small or large cornea, there is a predisposition to the development of glaucoma. As an acquired pathology, a decrease in the size of the cornea accompanies the subatrophy of the eyeball. In these cases, the cornea becomes opaque.

Embryotoxone is a ring-shaped opacification of the cornea, located concentrically in the limbus. It is very similar to an old arc. Treatment is not required.

The flat cornea can be combined with the microcornea, its refraction is reduced (28-29 D), there is a predisposition to increased intraocular pressure due to the narrowing of the anterior chamber angle.

[1], [2], [3]

The pathology of the iris in combination with the posterior embryotoxone

Rieger anomaly

• Hypoplasia of the mesodermal leaf of the iris.
• Iridotrabecular strands to the Schwalbe line.
• Rear embryotoxone.
• Ectropion of the choroid.
• Coliboma of the iris.
• Myopia of a high degree.
• Retinal disinsertion.
• Glaucoma - at least in 60% of cases.
• The corneal opacities are usually of a small size and located on the periphery.
• Posterior keratoconus.
• Cataracts are local opacities in the cortical layers of the lens, the visual acuity is affected little.
• Anomalies of the optic disc: an oblique disc of the optic nerve, myelin fibers.

Rigger's syndrome

Rigger syndrome is characterized by eye symptoms of Rieger anomaly and general manifestations, including:

• upper jaw hypoplasia;
• short labial groove;
• pathology of the teeth - small, conical teeth with wide gaps in the dentition, partial anodontia;
• umbilical and inguinal hernia;
• hypospadias;
• isolated hormonal insufficiency;
• heart valve defects.

The pathology of chromosome 6, deletion of 13 chromosomes (4q25-4q27) was revealed. The disease is inherited by an autosomal dominant type. Concomitant glaucoma occurs with a frequency of 25 to 50%.

The disease in most cases is inherited by autosomal dominant type, in 30% there are newly emerged mutations and sporadic appearance of anomaly.

Other syndromes, including developmental disorders of the anterior segment, include:

• Mikel's syndrome (Michel). Disease with autosomal recessive type of inheritance. Combines cleft lip and palate in combination with epicanthus, telecanthus, ptosis, telangiectasias of conjunctival vessels, peripheral opacities of the cornea, iridocorneal fusion and decreased intelligence.
• Oculo-dento-digital syndrome. Autosomal dominant syndrome, including microphthalmos, iris hypoplasia, persistent pupillary membrane, small nose and hypoplasia of the nose wings, constriction and shortening of the ocular gap, telecanthus, epicanthus, rare eyebrows, hypoplasia of tooth enamel, camptodactyly or syndactyly. The combination of the pathology of the anterior chamber angle with iridodysgenesis predisposes to the development of glaucoma in affected individuals.

Total change in the cornea

Flat cornea

The diagnosis of a flat cornea is set when the curvature of the cornea is in the range of 20-40 D. The keratometry data usually do not exceed the corresponding sclera parameters. Anomaly can be either unilateral or bilateral. A flat cornea may be accompanied by infantile glaucoma, aniridia, congenital cataracts, ectopia of the lens, colobomas, a symptom of blue sclera, microphthalmos and retinal dysplasia. The type of inheritance can be either autosomal dominant or autosomal recessive.

Local and diffuse corneal opacities

• Congenital glaucoma.
• Sclerocornea.
• Dystrophies of the cornea (in particular, congenital hereditary endothelial dystrophy).
• Pronounced dysgenesis of anterior segment of eye.
• Damage by chemicals.
• Fetal alcohol syndrome.
• Infectious keratitis (see Chapter 5).
• Non-infectious keratitis (see below).
• Diseases of the skin.
• Mucopolysaccharidosis.
• Cystinosis.

Peripheral opacities of the cornea

Dermoid

Dermoid cysts localized at the periphery of the cornea, as a rule, contain connective collagen and epithelial tissues, which gives them the appearance of dense whitish formations. Epibulbar dermoids are located on the conjunctiva, sclera, cornea or in the limb. Can represent an isolated pathology, and can enter into a symptomatic-plex of a circular dermoid syndrome - defeat by the dermoid of the entire circumference of the limb, 360 °. Sometimes dermoid corneal cysts are combined with dermoids of the conjunctiva and sclera, causing the appearance of corneal astigmatism, amblyopia and strabismus.

Sclerocornea

Congenital bilateral vascularized peripheral opacity of the cornea, often asymmetric. In 50% of cases, the disorder is sporadic, and in 50% - inherited by autosomal recessive type .. It can be accompanied by another pathology of the organ of vision, including:

• microcornea;
• flat cornea;
• glaucoma;
• dysgenesis of the anterior chamber angle;
• strabismus;
• nystagmus.

In rare cases, it accompanies such general disorders as:

• spina bifida;
• mental retardation;
• pathology of the cerebellum;
• the Hallerman-Streiff syndrome (Haller-man-Streiff);
• Mietens syndrome;
• syndrome Smith-Lemli-Opitsa (Smith-Lemli-Opitz);
• violation of osteogenesis;
• hereditary osteomyodysplasia - with this syndrome, if glaucoma does not join, usually high visual acuity is maintained.

Central corneal opacity

The anomaly of Peters

Usually a bilateral disorder characterized by the presence of central opacities of the cornea with a transparent periphery. Changes in the cornea are often accompanied by cataracts. Anomaly can have both an isolated character and be combined with another pathology of the organ of vision, including:

• glaucoma;
• microcornea;
• microphthalmos;
• flat cornea;
• Kolobory;
• mesodermal dystrophy of the iris.

In some cases, this pathology is included in the symptomatic complex of Peters's syndrome "plus", which includes low growth, cleft lip or palate, hearing damage and delayed development.

Other syndromes characterized by Peters anomaly:

• fetal alcohol syndrome;
• ring pathology of 21 chromosomes;
• partial deletion of the long arm of chromosome 11;
• the Warburg syndrome.

Medical measures in the anomaly of Peters are aimed at identifying and treating concomitant glaucoma, as well as, if possible, ensuring the transparency of the optical center of the cornea. The results of through keratoplasty with Peters anomaly remain unsatisfactory. Most authors indicate that keratoplasty is indicated only in cases of severe bilateral damage to the cornea. With opacification of the central zone of the cornea and the lens, optical iridectomy is possible.

Posterior keratoconus

A rare congenital bilateral syndrome that does not tend to progress. The curvature of the anterior surface of the cornea is not changed, however, a thickening of the stroma of the cornea is noted, and as a result, the curvature of the posterior surface of the cornea increases. As a result of these changes, myopic astigmatism occurs.

[4], [5], [6], [7], [8], [9], [10],

Primary pathology of the anterior chamber

The posterior border of the descemet membrane is indicated by the Schwalbe ring. Its anterior margin, which looks like a narrow grayish-white line, can be seen with tonyoscopy and is known as the posterior embryoscope.

The posterior embryotoxone is present on the gonio-skopic pattern of many healthy eyes. However, if the development of the anterior segment is disturbed, the posterior embryotoxone enters the symptom-complex of several known syndromes.

The anomaly of Axenfeld

The anomaly of Axenfeld includes a posterior embryotoxone in combination with iridogoniodogenesis (fusion of the root of the iris with the Schwalbe ring). It can have a sporadic origin, and can be inherited by an autosomal dominant type. In 50% of cases, glaucoma develops.

Congenital glaucoma

It is a blockade of the trabecular zone that is not absorbed by cell elements in the process of embryogenesis.

Alagill syndrome

Disease with autosomal dominant type of inheritance, characterized by congenital intrahepatic hypoplasia of the bile duct causing jaundice. The posterior embryotoxone is seen in more than 90% of patients. The ocular bottom has a paler color than normal. Often there are druses of the optic disc. Co-morbid disorders include the developmental defects of the spine (defect of anterior butterfly-shaped bowels), cardiovascular malformations, deep-set eyes, hypertelorism and pointed chin. Concomitant pigmentary retinopathy can be caused by vitamin A and vitamin E vitamin deficiency.