Causes of uveitis

Uveitis are found in all countries. Their etiology and distribution are closely related to the living conditions of the population, the circulation of pathogens, the presence of conditions, for the transmission of infection to susceptible individuals.

Data on the frequency of uveitis of different etiology vary widely, due to the epidemiological situation in different areas, the methods and evaluation criteria used for diagnosis. Over the past twenty years, there have been many reports of lesions of the uveal tract, retina and optic nerve caused by viruses, but it is very difficult to accurately determine the percentage of viral uveitis due to an ambiguous approach to their diagnosis.

The leading role as causative and triggering factors of uveitis is played by infections, and uveitis also develops in systemic and syndromic diseases. Among the infectious agents of greatest importance are tuberculosis, toxoplasmosis, streptococcal and viral infections. Infectious uveitis is 43.5% of the uveitis.

Later, the following changes occurred in the epidemiology and clinic of bacterial uveitis:

• decrease in the incidence of metastatic tuberculosis of the organ of vision with the increase of tuberculosis-allergic lesions of the anterior and posterior segments of the eye. The leading role is played by chronic forms of tuberculosis;
• a relatively high incidence of uveitis in toxoplasmosis and streptococcal infection;
• the tendency to increase the frequency of uveitis in systemic and syndromic diseases in children and adults against the background of eye hypersensitivity to streptococcus and inhibition of cellular immunity;
• an increase in the frequency of infectious-allergic uveitis on the background of bacterial and herpesviral polyallergies, tissue sensitization, and various disorders of reactivity.

At present, the following pathological classification of uveitis is most acceptable.

1. Infectious and infectious-allergic uveitis:
   • virus;
   • bacterial;
   • parasitic;
   • fungal:
2. Allergic non-infectious uveitis arising from hereditary allergies to external and internal factors (atopic), uveitis in drug, food allergies, whey uveitis with the introduction of various vaccines, sera and other non-infectious antigens, heterochromic cyclite Fuchs.
3. Uveitis in systemic and syndromic diseases - with diffuse involvement of connective tissue (rheumatism, rheumatoid arthritis, spondylitis, sarcoidosis, Vogt - Koyanachi - Harad, Reiter syndromes), multiple sclerosis, psoriasis, glomerulonephritis, ulcerative colitis, autoimmune thyroiditis.
4. Post-traumatic uveitis, developing after penetrating eye injury, contusion and post-operation, phacogenic iridocyclitis, systematic ophthalmia.
5. Uveitis with other pathological conditions of the body: in violation of the exchange and functions of the neurohormonal system (with menopause, diabetes), toxic-allergic iridocyclitis (with the decay of the tumor, blood clots, retinal detachment, blood diseases).

With the introduction of the practice of the method of cycloscopy, inflammation of the flat part of the ciliary body and the extreme periphery of the vascular membrane proper, peripheral uveitis, began to be isolated.

Panoveitis and peripheral uveitis are relatively rare, with anterior uveitis often occurring, go iridocyclitis.

There are primary, secondary and endogenous forms of inflammation. Primary uveitis occurs on the basis of common diseases of the body, and secondary develops with ophthalmic diseases (keratitis, scleritis, retinitis, etc.). The main cause of vascular disease is endogenous uveitis. Diseases of the vascular tract, caused by common diseases of the body, can be both metastatic and toxic-allergic (with sensitization of the body and eyes). Exogenous uveitis develops with penetrating wounds of the eyeball, after operations, perforated corneal ulcers.

The clinical course of uveitis is divided into acute and chronic. However, this division is arbitrary, since acute uveitis can change into chronic or chronically recurrent. There are also focal and diffuse uveitis, and according to the morphological picture of inflammation - granulomatous and non-granulomatous. Granulomatous include metastatic hematogenous uveitis, and non-granulomatous uveitis, which are caused by toxic or toxic-allergenic influences. There are also mixed forms of uveitis.

By the nature of the process or inflammation, the following forms of uveitis are distinguished:

1. fibrous-lamellar;
2. serous;
3. festering;
4. hemorrhagic;
5. mixed.

The posterior uveitis, or choroiditis, is usually classified by localization of the process, separating the central, parantental, equatorial and peripheral ones. There are also limited and disseminated choroiditis. Acute inflammation often corresponds to exudative-infiltrative process, chronic - infiltrative-productive.

[1], [2], [3], [4]