Allergic uveitis: causes, symptoms, diagnosis, treatment

In the immunopathology of the visual organ, the vascular tract is given leading importance, as evidenced by a large number of published works. Research has been especially intensive in recent years. Increased interest in this part of the eyeball is explained by the fact that allergy is very widely represented in its pathology, diseases are widespread, often characterized by a severe course and a bad outcome, their diagnosis is difficult, and treatment does not always satisfy patients.

The tissues of the uveal tract are highly sensitive to a variety of allergens, among which endogenous irritants brought by the blood predominate. Apparently, a massive influx of allergens causes immediate reactions in the uveal tract with a predominance of the exudative component, while the vascular membrane responds to less intense but longer effects mainly with proliferation.

According to the well-known classification of Woods (1956), all inflammatory diseases of the vascular tract are divided into granulomatous and non-granulomatous. The position that the cause of granulomatous lesions is hematogenous introduction of an infectious agent from some focus in the body is increasingly being asserted. Infection agents enter the eye and cause the formation of specific granulomas characteristic of them in the vascular tract. Depending on the type of infection, the clinical picture of these diseases has its own differences, facilitating the etiological diagnosis, but they are rarely observed.

Non-granulomatous uveitis, reflecting reactions of sensitized uveal tissue to endogenous, less often exogenous allergens, develops mainly as allergic processes. Manifested as plastic, serous-plastic and serous anterior uveitis, panuveitis and diffuse posterior uveitis, these often very severe diseases have almost no signs that would convincingly indicate one or another etiology. Ascertaining this, as a rule, requires a special allergic examination of the patient.

Most often, non-granulomatous uveal processes are caused by general chronic infections. Along with tuberculosis, toxoplasmosis, viral and other infections, streptococci of hidden focal foci of infection occupy a large place in the development of infectious-allergic uveitis. With the help of appropriate allergens, this infection is detected in 2-20% of patients with uveitis of unclear etiology and can be superimposed on tuberculosis and other eye diseases.

The vascular tract is very susceptible to autoimmune reactions, often manifested by severe uveitis. The irritants are antigens that arise as a result of metabolic disorders in patients with diabetes, gout, diathesis, liver pathology, blood, etc. The allergic component in the pathogenesis of uveal lesions on the basis of such sufferings always takes place, worsens the course of the disease and complicates its treatment, since the most active immunosuppressive agents are often contraindicated for such patients.

The choroid is very sensitive to allergens arising from the eye's own tissues during mechanical, chemical, physical and other damage. The high allergenicity of the corneal endothelium was noted above, but it is no less high in the tissue of the vascular itself (its melanin pigment - tapten) and the retina. Sensitization of the eye (and the body) by its own allergens during burns, penetrating wounds, contusions, radiation, cold and other effects leads to the formation of corresponding autoantibodies, and further entry of the same antigens from pathological foci of the eye or non-specific effects cause the development of immediate-type allergic reactions extending beyond the damaged area. This is, in particular, the mechanism, presented here in a very simplified form, of one of the most important features of the pathogenesis of eye burns and aseptic traumatic iridocyclitis. Recognition of allergic factors as leading in the indicated pathology allows us to justify its corticosteroid and other antiallergic therapy, which, as is known, gives a pronounced effect in many patients.

S. E. Stukalov (1975) and many other researchers classify sympathetic ophthalmia as an autoimmune disease, thereby confirming the validity of the “antigenic anaphylactic theory of sympathetic inflammation” put forward by A. Elschnig at the beginning of our century.

Oculogenic allergic uveitis in patients with old, non-adherent retinal detachments or with disintegrating intraocular tumors is essentially autoimmune.

The lens occupies a special place in ophthalmoallergology. Even its unchanged substance, being outside the capsule for some reason, is not tolerated by the eye: the body's immunological tolerance to the lens tissue is absent. Such tissues are called primary or natural allergens. Every ophthalmologist has had to observe how violently, up to endophthalmitis, the eye reacts to the lens masses falling into the anterior chamber during penetrating wounds, what severe inflammations complicate overripening and overripe cataracts. Some authors consider such processes phacotoxic, others cautiously talk about "phacogenic" inflammations, and others confidently call them phacoanaphylactic iridocyclitis and endophthalmitis.

The divergence of opinions indicates that the pathogenesis of the eye's reactions to the lens tissues is far from being revealed, and much does not fit into the framework of conventional ideas. For example, skin tests with lens antigen are unconvincing, and any therapeutic treatment is useless. The eye can only be saved by emergency release of the lens and its masses.

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