Metabolic disorders with corneal involvement

In metabolic diseases, any of the corneal layers can be involved in the pathological process.

Pathology of the epithelium

The epithelium of the cornea can be stained with toxic substances or be involved in the pathological process with certain metabolic disorders.

• Chloroquine diphosphate and hydroxychlorine sulfate are ring-shaped opacities.
• Amiodarone - characteristic curls, gentle point clouding.

Subepithelial pathology

These are subepithelial linear opacities, having a radial direction and located in the upper half of the cornea. Frequent satellites of enteropathic acrodermatitis. These changes are characterized by a whorled form. The process can be complicated by keratomalacia.

Symptoms of general pathology include nail dystrophy, digestive system disorders that cause diarrhea and slow growth of the baby.

As a therapeutic measure, a diet enriched with zinc is prescribed.

Stroma

With cystinosis, there is a disruption of the transport function of lysosomes and the deposition of cysteine in them. Crystals of cysteine, accumulating in the anterior sections of the stroma, cause a thickening of the cornea, a disorder of its sensitivity, the development of surface point keratopathy and recurrent erosions.

The accompanying cystinositis pathology includes developmental delay, kidney disease, depigmentation of hair and skin, pigment retinopathy. Emerging in early childhood, cystinosis leads to kidney failure and early death. Developing in adults, the disease does not affect the kidneys and is limited to corneal manifestations. Debuting in adolescents, cystinosis in clinical manifestations resembles an infantile form, but with no delay in development and changes in skin.

Cysteamine is highly effective. With a significant decrease in vision, continuous keratoplasty is indicated.

Descemet Membrane

Wilson's disease (Wilson) is a hereditary disease with a disorder of copper metabolism. With this pathology, the level of protein transporting copper is reduced in serum, but increased in tissues. Apparently, the pathological gene is similar to the Menkes gene and is localized in the 3ql4.3 zone. The disorder often manifests itself by staining the Descemet's membrane at the periphery of the cornea, especially intense at 12 and 6 hours.

[1], [2], [3], [4], [5], [6], [7], [8], [9], [10]

Deposition of crystals in the cornea

The deposition of crystals in the cornea occurs under the following conditions:

1. cystinosis;
2. crystalline degeneration of the cornea (Schnyder's dystrophy);
3. deficiency of lecithin-cholesterol-acyltransferase;
4. crystals of uric acid;
5. granular dystrophy and marginal dystrophy of Bietti (Bietti);
6. multiple myeloma; monoclonal gammopathy;
7. calcium deposition;
8. syndrome of crystal deposition in the cornea, myopathy, nephropathy;
9. tyrosinemia type II.

In the early stages of the disease, this symptom can be established only with the help of gonioskopia.

Related changes include:

• degeneration of the basal ganglion with the appearance of a tremor;
• choreoathetosis;
• changes in the nervous system and psyche;
• staining kidney tubules with the appearance of aminoaciduria;
• nodular form of cirrhosis.

Sometimes, with Wilson's disease, cataracts resemble a sunflower flower (see Chapter 14). Treatment with penicillamine does not always provide an effect, liver transplantation may be required.

[11], [12], [13], [14], [15]

Lentoid keratopathy

Lentoid keratopathy is the result of impregnation of the Bowman membrane with calcium. The primary cause is, as a rule, a chronic inflammatory process or a systemic disease. Calcium deposition is initially localized within the eye gap.

Lentoid keratopathy is a frequent companion of such common disorders as sarcoidosis, paraty-rheoid pathology and multiple myeloma.

In many cases, ribbon-like keratopathy is a companion of chronic inflammatory processes such as juvenile rheumatoid arthritis, Still disease and sarcoidosis.

With this pathology, chelation preparations are effective. In some cases, ribbon-like keratopathy develops at the terminal stages of the phthisis of the eyeball.

Deficiency of lecithin-cholesterol-acyltransferase

The disease is inherited by autosomal recessive type. In homozygous states and in preterm there is a central tender opacity of the cornea, and in heterozygous - arcus senilis arises . Concomitant common diseases include renal failure, anemia and hyperlipidemia.

[16], [17], [18]

Arcuate degeneration of the cornea

Lipoid arches of the cornea develop due to the deposition in the peripheral sections of the stroma of phospholipids, low density lipoproteins and triglycerides. The arc is more often formed in young people and accompanies the following diseases:

• familial hypercholesterolemia (Friederickson syndrome, type II);
• family hyerlipoproteinemia (type III);
• pathological processes associated with corneal diseases, such as spring keratopathy or herpes simplex.
• primary lipoidal degeneration of the cornea.

The formation of the arc can also occur in healthy people with a normal level of lipids in the blood plasma.

[19], [20], [21]