Fungal eye lesions: causes, symptoms, diagnosis, treatment

Fungal infections of the visual organ have been known for over 100 years. For a long time, this pathology was considered very rare, dangerous types of fungi for the eyes were counted in units, publications about the diseases caused by them were mainly casuistic. However, starting in the 1950s, reports of such diseases became more frequent. Often, a significant number of observations are given, previously unknown fungal eye lesions and new representatives of fungal flora causing them for ophthalmologists are described, the clinical picture, diagnostics and prevention are specified, more effective methods of treating ophthalmomycosis are proposed.

Currently, up to 50 types of fungi are considered pathogenic for the visual organ. The most important of them are yeast-like, mold mycetes, dermatophytes, etc.

In most patients with ophthalmomycosis, fungi penetrate into the eye tissue from the environment or are brought in from mycotic foci on the skin and mucous membranes of other parts of the body, less often they come from such and deeper sources by the hematogenous route. Exogenous fungal infection usually causes mycoses of the appendages and anterior part of the eyeball. Endogenous introduction often causes severe intraocular processes.

Of great importance in the inoculation of fungal infection into the tissues of the eyelids, conjunctiva and eyeball are injuries to the latter, most often small abrasions and erosions, superficial foreign bodies of the conjunctiva and cornea, especially derivatives of the plant world. For example, of the 33 patients with keratomycosis observed by FM Polack et al. (1971), only 4 did not have a history of eye damage. Fungi penetrate into the eye through penetrating wounds. Most often, ophthalmomycosis affects rural residents, workers in elevators, grain storage facilities, mills, cotton gins, weaving factories, feed shops, livestock breeders, etc.

Fungal diseases are easier to develop and worsen, especially in early childhood, when the body is weakened due to general infections, nutritional disorders, metabolic disorders. For such patients, even the most harmless fungi - human saprophytes - become pathogenic.

Unlike infectious eye diseases of bacterial and viral genesis, drug therapy is ineffective in fungal diseases. All authors unanimously acknowledge the widespread, not always rational, local and general use of antibiotics and corticosteroids for the treatment of a wide variety of human diseases as one of the important reasons for the growth of fungal eye diseases in recent decades.

The validity of this opinion is confirmed by clinical observations and experimental studies. Thus, H. V. Nema et al. (1968) after a month-long treatment of the conjunctiva found previously absent fungal flora in the conjunctival sac in 41.2% of patients treated with hydrocortisone and in 28.7% of patients receiving tetracycline. Similar data are provided by L. Nollimson et al. (1972) regarding betamethasone and neomycin. According to I. I. Merkulov, antibiotics disrupt the antagonistic relationship between bacteria and fungi in favor of the latter, and corticosteroids reduce the protective abilities of tissues. In addition, some fungi, in particular Candida albicans and Aspergillus niger, grow better and become more pathogenic in the presence of corticosteroids. The growth of fungi, especially Candida albicans, is also promoted by B vitamins.

The above-mentioned features of fungal infection are characteristic not only of eye processes; they manifest themselves in many other localizations of mycoses. Nevertheless, it is important for ophthalmologists that the visual organ is no exception to the general patterns of fungal lesions in humans. If a patient seeking eye care has developed an inflammatory eye disease against the background of mycosis in other parts of the body, the disease was preceded by even a minor injury, the patient could have become infected with a fungal infection due to living and working conditions, and an attempt to treat with antibiotics, sulfonamides, and corticosteroids was unsuccessful, then there is every reason to suspect ophthalmomycosis. In cases where the clinical picture of the eye disease contains signs characteristic of a fungal infection, the above factors are additional data. However, to establish an accurate diagnosis of ocular mycosis, it is necessary to isolate a fungal culture, determine its type, confirm that it was this pathogen that caused the eye disease in this patient, and clarify the sensitivity of the isolated culture to antifungal agents. Quick and unambiguous answers to these questions cannot always be obtained. In widespread practice, the etiology of an eye disease is often assessed as mycological only on the basis of anamnestic data, the clinical picture of the eye process, detection of extraocular foci of mycosis and trial treatment with antifungal agents. Naturally, with this approach, some ophthalmomycoses, especially when superimposed on viral and bacterial eye diseases, remain unrecognized. It is advisable to resort to laboratory mycological studies as often as possible when ophthalmomycosis is suspected.

Despite the diversity of pathogens and manifestations of fungal eye lesions, their clinical features are characterized by some common qualities. Thus, the incubation period from the time of introduction of a fungal infection to the appearance of the first signs of eye disease varies from 10 hours to 3 weeks. Symptoms, as a rule, develop slowly, and the process is often chronic in nature without a tendency to spontaneous attenuation. There are always external manifestations of inflammation expressed to varying degrees: hyperemia, purulent discharge, tissue infiltration and ulceration, delayed reparation of defects. A number of fungal eye invasions are characterized by the formation of granuloma-type nodes in the skin of the eyelids, conjunctiva, orbit, vascular tract, their suppuration with the development of fistulas, skin bridges, the presence of grains of fungal mycelium in the discharge, the formation of concretions in the lacrimal canals and glands of the conjunctiva, the crumbly nature of the infiltrates, their yellowish or grayish-yellow color, etc. At the same time, most fungal eye infections are characterized by individual differences depending on the type of fungus, localization and prevalence of the lesion, the condition of the tissues preceding the mycosis, general health, reactivity of the body, even hereditary predisposition to fungal diseases. The first group of signs facilitates the general diagnosis of eye mycosis, the second helps to suspect a certain type of fungus, which is important when choosing treatment methods and means.

Histologically, in preparations and sections of eye tissues affected by fungi, damage to the integrity of the epithelium and performance of its cells, nonspecific granulomas of leukocytes, lymphocytes, histiocytes, epithelioid and other cells, pseudobio.ch and dystrophic changes around such granulomas are determined. With the help of special stains (Gridl, Gomori, etc. methods), mycelium and spores of the pathogen are often detected in such preparations, as well as in scrapings from ulcers of the conjunctiva and cornea. Some types of fungi, such as Candida albicans, cause only leukocyte and eosinophilic infiltration of the membranes and suppuration of the internal; media of the eyeball.

Fungal pathology of the eye and its accessory apparatus is caused not only by direct introduction of pathogens into their tissues. It often develops as an allergic reaction to fungal allergens coming from mycotic foci distant from the eye. In persistent eye processes that do not heal for years, such foci are found under the crowns and bridges of teeth in the oral cavity, in the interdigital folds of the feet, in the vagina. Sometimes the cause of allergies was onychomycosis. A sharply expressed reaction to trichophytosis (skin test) and rapid recovery of the eyes after the elimination of extraocular foci are strong evidence of the allergic nature of this pathology.

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Treatment of fungal diseases of the organ of vision

Treatment of fungal diseases of humans in general is currently carried out primarily by special antimycotic agents, the arsenal of which is significant, and the efficiency is quite high. Timely initiation and purposeful therapy, selected in accordance with clinical data and the characteristics of the isolated cultures of pathogens, is the most successful. Most often than other means of such therapy in general mycology, they resort to antifungal antibiotics: nystatin, active against yeast-like and mold fungi, amphotericin B and amphoglucocamine, affecting the causative agents of coccidioidomycosis, cryptococcosis, blastomycosis, mold and other fungi, levorin, affecting fungi of the genus Candida, griseofulvin, effective against epidermophytosis, trichophytosis, microsporia. Of the other fungicidal agents acting on fungi, decamin and decamethoxin, useful for candidomycosis, nitrofurylene, nitrofran, esulan, amikazol, ointments "Tsinkundan", "Undecin" and a number of other drugs are used mainly in dermatology.

When prescribing general treatment with fungicidal agents, one should strictly follow the above-mentioned manual, since many of these agents, especially amphotericin B, griseofulvin, etc., are highly toxic. There are many contraindications to their use, and they require compliance with a number of conditions for their use. Eye forms of fungicidal agents for topical use are: amphotericin B eye drops (0.25%, 0.5%, and 1%) and eye ointment (0.5%), levorin eye drops (1% and 2.5%) and eye ointment (2.5%), nystatin eye drops (1%), subconjunctival injection solution (1-2.5%), and eye ointment (5%). The prescriptions for the solution for subconjunctival injection of amphotericin B (0.015 g in 0.2 ml of water), eye drops of grisemin (0.5%) and decamin (0.1%) are given in the handbook of ophthalmology published in 1967. Using the prescriptions given in these handbooks, ophthalmologists have the opportunity to supplement the general treatment of ophthalmomycosis with local administration of the most effective antifungal agents, sometimes limit themselves to local treatment only, and also use these agents to sanitize the conjunctival cavity from fungal flora. Electrophoresis of antifungal drugs has been successfully tested in ophthalmology.

In the treatment of certain types of fungal infections of the visual organ, iodine preparations, aniline dyes, and disinfectants, which have been used for a long time, have not lost their importance. Surgical interventions, from simple scraping of foci and opening of abscesses to keratoplasty and vitreectomy, often give good results.