Congenital cataracts

Congenital cataracts develop as a result of intrauterine pathology and are often combined with various developmental defects of both the eye and other organs.

Congenital cataract is a clouding of the lens that is present at birth or appears shortly thereafter.

Congenital cataracts may be sporadic or may develop from chromosomal abnormalities, metabolic diseases (eg, galactosemia), or congenital infections (eg, rubella), or maternal illnesses during pregnancy. Cataracts may be nuclear or may involve the lens substance under the anterior or posterior capsule. They may be unilateral or bilateral. Cataracts may go unnoticed unless the infant's red reflex is checked or an ophthalmoscopy is performed at birth. As with other types of cataracts, clouding of the lens impairs vision. Cataracts may obscure the view of the optic disc and vascular fundus and should be evaluated by an ophthalmologist.

Congenital cataracts can occur under the influence of various toxic substances on the embryo and fetus during the formation of the lens. Most often, this occurs when the mother suffers from viral infections during pregnancy: flu, measles, rubella, and toxoplasmosis. Various endocrine disorders in women during pregnancy and insufficiency of the paraaditoid glands (for example, hypocalcemia, leading to fetal developmental disorders) have a great influence. Congenital cataracts are often familial. Most often, congenital cataracts are bilateral, but unilateral congenital cataracts also occur.

Congenital diseases of the lens are divided into cataracts, changes in shape, size, dislocation of the lens, coloboma and absence of the lens.

Congenital dislocations of the lens occur in hereditary disorders of connective tissue metabolism and anomalies in the skeletal system.

Marfan syndrome - a small lens with its subluxation is a manifestation of this syndrome. In addition, it is characterized by damage to the cardiovascular system in the form of heart defects, aortic aneurysm. The musculoskeletal system changes in the form of arachnodactyly (long fingers and toes), dolichocephaly (increase in the longitudinal dimensions of the head), brittle bones, frequent dislocations, tall stature, long limbs, scoliosis, funnel chest, underdevelopment of the mouse and genitals. Less common is a change in mentality. The eye is affected in 50-100% of cases. Ectopia of the lens, changes in its shape are caused by underdevelopment of the ligaments that support it. With age, the rupture of the Zinn ligament increases. In this place, the vitreous body protrudes in the form of a hernia. A complete dislocation of the lens is also possible. There may be cataracts, strabismus, nystagmus and other eye syndromes, congenital glaucoma.

Margetapie syndrome is a systemic hereditary lesion of mesenchymal tissue. Patients with this syndrome have short stature, short limbs, an enlarged head size (brachycephaly), limited joint mobility, changes in the cardiovascular system and other organs. On the part of the lens - ectopia downwards, spherophakia, microphakia, etc.; myopia, retinal detachment, congenital glaucoma.

Change in the shape and size of the lens - lenticonus - a cone-shaped protrusion of one of the surfaces of the lens. A protrusion (like an additional small lens) appears in the lens, which can be on the front and back surface, it is transparent. In transmitted light, a round formation in the form of a drop of oil in water can be seen against the background of the lens. This section has a very strong refraction, is always accompanied by myopia (there may be pseudomyopia). In these protrusions there are seals - a core with high refractive power.

Depending on the size of the lens, a distinction is made between:

• microphakia (small lens, usually with a change in shape; the equator is visible in the pupil area; lens dislocation often occurs);
• spherophakia (spherical lens), annular lens (the lens in the center has been absorbed for some reason). With a narrow pupil, the lens is not visible. With a dilated pupil, a ring remains under the cornea, usually cloudy;
• biphacigo (two lenses), which is very rare. One lens is located temporally or nasally, or the lenses are located one above the other,

Coloboma of the lens is a defect of the lens tissue and the lower part, which is formed as a result of incomplete closure of the embryonic fissure during the formation of the secondary ocular bulge. This pathology is very rare and is usually combined with coloboma of the iris, ciliary body and choroid.

Congenital cataract - "waterfall". Of all congenital defects, it occurs in 60% of cases, in every fifth person per 100 thousand of the population.

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Capsular congenital cataract

Polar (anterior and posterior) cataracts. Anterior polar cataract is a cataract of a very early period of embryogenesis (the first month of intrauterine life of the embryo). Limited white opacity at the anterior pole of the lens occurs during the period when the optic vesicles are formed in the anterior cerebral end, growing towards the outer ectoderm. From the side of the outer ectoderm, the lens begins to grow during the same period. The latter presses in the optic vesicle, and the optic cup is formed. The development of anterior polar cataract is associated with a disorder in the detachment of the lens rudiment from the ectoderm. Anterior polar cataract can also develop as a result of other intrauterine inflammatory processes, as well as after birth as a result of a perforating ulcer of the cornea. With anterior polar cataract, a limited white opacity of no more than 2 mm in diameter is determined, located in the center of the lens surface. This opacity consists of severely altered, malformed, cloudy lens fibers located beneath the lens capsule.

Posterior polar cataract is a cataract of late embryogenesis. It is formed in the prenatal period. In essence, with such a cataract, a callus is formed on the posterior capsule of the lens. It is believed that this is a remnant of the vitreous artery, which is reduced by the time the child is born.

Clinically, a limited clouding of a rounded shape of grayish-white color is determined, located at the posterior pole of the lens. There may be diffuse clouding, which consists of individual points, or it may be layered.

A variety is the pyramidal cataract. In addition to the opacity, there is a protrusion in the pole area, i.e. it proliferates into the vitreous body in the form of a pyramid. Since polar cataracts are always congenital, they are bilateral. Due to their small size, they usually do not lead to significant impairment of central vision and are not subject to surgical treatment.

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Capsulolenticular cataract

Fusiform cataract - opacity - is located in the area of the posterior and anterior poles, which are connected by a bridge. The opacity is presented in the form of a thin gray ribbon, resembles a spindle and consists of three thickenings. Such opacity can also be located in the area of the nucleus. Vision is slightly reduced. Such cataracts usually do not progress. From early childhood, patients adapt to looking through the transparent areas of the lens. Treatment is not required,

Lenticular cataract:

• anterior axial embryonic cataract. Occurs in 20% of healthy individuals. Very subtle opacity in the anterior region, anterior-posterior axis of the lens, at the suture of the embryonic nucleus. Does not affect vision;
• stellate (suture cataract) - clouding along the sutures of the embryonic nucleus. Crumbs resembling semolina are visible on the sutures. Occurs in 20% of healthy individuals. The child retains fairly high visual acuity;
• central nuclear cataract. There are three subtypes: powdery cataract - diffuse opacification of the embryonic nucleus, which consists of small-point bullet-shaped opacities, vision is practically not reduced; saturated opacification - with it vision is not multi-point cataract - many point opacities of grayish and bluish color in the area of the embryonic nucleus.

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Zonular (laminated) cataract

Zonular cataract (layered) is the most common form of congenital cataracts - 60%. Bilateral cataracts are more common. The opacity is presented in the form of a cloudy disk, which is located on the border of the adult and embryonic nuclei. This cataract is characterized by alternating transparent and cloudy layers of the lens. Along the equator in the zone of the adult nucleus there is a second layer of opacity, separated from the first by a layer of transparent fibers. The opacity of the second layer is wedge-shaped, and is non-uniform in intensity.

In transmitted light, a red reflex is visible on the periphery, and a gray opacity is visible in the center. The edge of the opaque disk is uneven, looped. It has been established that zonular cataract is not only congenital. It can also occur in the postnatal period in children suffering from spasmophilia against the background of hypocalcemia, who have had rickets, with hypoglycemia. Vision suffers depending on the degree of opacity of the lens.

Discoid congenital cataract is similar to zonular cataract, but there is no unevenness and loopiness of the edge of the cloudy disc.

Blue cataract - multiple opacities of a bluish tint. Opacities are localized between the nucleus and the capsule.

Complete cataract is a diffuse clouding of the entire lens that may develop from a lamellar cataract. Plaques are sometimes visible under the capsule.

Semi-resolved cataract - the lens seems to dry out, becomes flat. Ultrasound helps to make a diagnosis. The thickness of the lens decreases to 1.5-2 mm, a film may remain instead.

Membranous cataract - a cloudy capsule and a small amount of lens substance.

Atypical and polymorphic cataract. The opacity varies in size and shape. For example, cataracts in measles rubella are characterized by a white opacity with a pearly hue. With a dilated pupil, an eccentrically located rod is visible against this background, in which the virus can live for a long time (several decades). The peripheral parts of the lens are more transparent.

Classification of congenital cataracts

Hereditary cataracts, their causes.

1. Genetic inferiority and heredity. Most often they arise according to the dominant type, but they can also occur according to the recipient type (especially in incest).
2. Hereditary disorders of carbohydrate metabolism - galactose-containing cataract.
3. Calcium metabolism disorder - tetanic cataract.
4. Hereditary skin lesions.

Hereditary cataracts are caused by damage to the gene and chromosomal apparatus.

Intrauterine cataracts:

1. embryopathies that occur during pregnancy up to eight weeks;
2. fetopathy that occurs after eight weeks of pregnancy.

Their clinical picture is similar,

Causes of intrauterine cataracts:

1. maternal diseases (rubella, cytomegathia, chickenpox, herpes, influenza and toxoplasmosis);
2. maternal intoxication (alcohol, ether, contraceptives, some abortive drugs);
3. cardiovascular diseases of the mother, which lead to oxygen starvation and the development of cataracts;
4. hypovitaminosis A and E, folic acid deficiency;
5. Rhesus conflict;
6. toxicosis of pregnancy.

Classification of congenital cataracts:

1. unilateral or bilateral lesion;
2. partial or complete;
3. localization of opacities (capsular, lenticular, capsulolenticular).

By clinical forms:

1. as a concomitant eye disease;
2. by visual acuity (Stage I > 0.3; Stage II 0.05-0.2; Stage III - 0.05)

Classification according to E.I. Kovalevsky:

1. by origin (hereditary and intrauterine);
2. by leading localization (polar, nuclear, zonular, diffuse, polymorphic, coronal);
3. by the degree of vision loss (Stage I > 0.3; Stage II 0.05-0.2; Stage III - 0.05);
4. by complications and associated changes:
   • without complications and changes in visual function;
   • cataract with complications (nystagmus, etc.);
   • cataract with associated changes (microphakia, etc.).

Clinical forms of congenital cataracts:

1. capsular and bursal cataracts;
2. capsulolenticular (both the capsule and the lens substance are affected);
3. lenticular;
4. cataracts of embryonic sutures;
5. zonular or layered.

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Treatment of congenital cataracts

Removal of congenital cataracts within 17 weeks of birth ensures development of vision and the visual pathways of the cerebral cortex. Cataracts are removed by aspirating them through a small incision. Many children can have an artificial lens implanted. Postoperative vision correction with glasses, contact lenses, or both is necessary to achieve good vision.

After removal of a unilateral cataract, the image quality from the operated eye is worse than that of the unoperated eye (assuming the other eye is normal). Since the better-seeing eye is preferred, the brain suppresses the poorer-quality image, and amblyopia develops (see above). Thus, treatment of amblyopia is necessary to develop normal vision in the operated eye. Some children, despite this, do not develop good visual acuity. In contrast, children with bilateral cataracts, in whom the image quality is the same in both eyes, more often develop equal vision in both eyes.

Some cataracts are partial (posterior lenticonus) and clouding develops within the first 10 days of life. Partial congenital cataracts have a better visual prognosis.