Corneal ulcer

A corneal ulcer occurs when pathogenic microflora (diplococcus, staphylococcus, streptococcus) gets onto corneal erosion or onto an ulcerated infiltrate after any superficial keratitis. In this case, eye irritation increases sharply, the eyelids swell. The bottom and edges of the erosion take on a gray-yellow color, the cornea around the ulcer swells greatly and becomes cloudy. Purulent bodies join the usual round-cell infiltrate of the cornea. The iris is very quickly involved in the inflammatory process. The fluid in the anterior chamber becomes cloudy, and pus almost always appears in it, which, due to gravity, accumulates in the lower part of the anterior chamber, limited from above by a horizontal line and taking the shape of a crescent. The accumulation of pus in the anterior chamber is called ginopion. It consists of leukocytes enclosed in a fibrin mesh. Ginopion is sterile if the cornea is intact.

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Symptoms of corneal ulcer

The course of purulent ulcers is more severe than simple ones. They tend to spread both on the surface and deep into the cornea, causing its perforation. To prevent the development of purulent ulcers, it is necessary to instill antibiotic solutions into the conjunctival cavity in case of corneal defects.

A special place in the clinical picture of keratitis with defects of the corneal surface is occupied by creeping corneal ulcer.

A creeping corneal ulcer begins with the appearance of a yellowish infiltrate in the cornea, almost always in its central area opposite the pupil, which consists of purulent bodies. When the purulent bodies disintegrate, a histological enzyme is released that melts the tissue; the infiltrate disintegrates, and an ulcer forms in its place, one edge of which is slightly raised, undermined, and surrounded by a strip of purulent infiltrate. This edge of the ulcer is called progressive. Pneumococci are found not only in the tissue of the infiltrated edge, but also in the surrounding healthy tissue of the cornea.

The opposite edge of the ulcer is clean, but its bottom is covered with a gray-yellow infiltrate.

The iris is involved in the process very early. Its color changes, the pattern is smoothed out, the pupil narrows, the pupillary edge of the iris fuses with the anterior capsule of the lens (posterior synechiae), pus appears in the anterior chamber, there are pronounced symptoms of eye irritation, severe pain, swelling of the eyelids, and a periconeal injection of purple color. A creeping corneal ulcer is a serious disease, but often, under the influence of timely correct treatment, it is cleared and the resulting defect is epithelialized. A depression (facet) remains at the site of the ulcer. Later, the facet is filled with connective tissue and a persistent intense opacity (leukoma) is formed.

Sometimes a creeping corneal ulcer spreads both on the surface and deep into the cornea, leading to its perforation. After perforation, the ulcer heals with subsequent scarring and the formation of a leukoma fused with the iris. In very severe cases, the cornea quickly melts, the infection penetrates into the eye, causing purulent inflammation of all the membranes of the eye (panophthalmitis). The eye tissues are destroyed, mixed with connective tissue, the eyeball atrophies.

A creeping corneal ulcer usually develops when pneumococcus, staphylococcus, streptococcus, and pseudomonas aeruginosa enter the erosion surface. Superficial damage to the cornea can be caused by small foreign bodies, tree leaves and branches, sharp awns of cereals and grains. Cases of creeping corneal ulcer are especially common in summer and early autumn during agricultural work.

The infection is introduced by the wounding body. Usually the pathogens are in the normal flora of the conjunctival cavity as a saprophyte. It is especially often found in the pus of the lacrimal sac in chronic purulent dacryocystitis. In approximately 50% of all cases, creeping ulcer develops in people suffering from chronic dacryocystitis or narrowing of the lacrimal-nasal canal.

The prognosis is always very serious. As a result of the central location of the ulcers, their scarring leads to a sharp decrease in visual acuity, a corneal leukoma is formed, fused with the iris.

If the causative agent is the Morax-Axenfeld bacillus (diplococcus), the corneal ulcer spreads very quickly into the depths, both edges are infiltrated, the hypopyon is of a viscous consistency.

The corneal ulcer in gonoblenorrhea has a whitish color, quickly spreads over the surface and deep, perforation and panophthalmitis quickly occur. The outcome is an extensive leukoma, staphyloma of the cornea.

With Pseudomonas aeruginosa, the abscess-like lesion quickly takes over the entire cornea, the anterior layers of the cornea peel off and hang down. The cornea melts within 24-48 hours, the ulcers quickly perforate. The eye dies.

Treatment of corneal ulcer

Prevention of corneal ulcers should be carried out with any, even minor, corneal injury: whether a speck of dust, an eyelash, or an accidental light scratch got in. In order to prevent corneal erosion from becoming an entry point for infection, it is enough to instill any antibacterial eye drops into the eye 2-3 times a day, and put an eye ointment with antibiotics behind the eyes at night.

The same is done when providing first aid to a patient diagnosed with superficial keratitis. Instillations of antibacterial drops should be carried out every hour until the patient is seen by a specialist. If the diagnosis of keratitis is made at an appointment with an ophthalmologist, first a smear of the contents of the conjunctival cavity or a scraping from the surface of the corneal ulcer is taken to identify the causative agent of the disease and determine its sensitivity to antibacterial drugs, then treatment is prescribed aimed at suppressing the infection and inflammatory infiltration, improving the trophism of the cornea. To suppress the infection, antibiotics are used: chloramphenicol, neomycin, kanamycin (drops and ointments), cipromed, okacin. The choice of antimicrobial drugs and their combination depend on the type of pathogen and its sensitivity to drugs. The drug of choice for gram-positive organisms is cerazolin, for gram-negative organisms - tobralinin or gentamicin. Cefazolin (50 mg/ml), tobramin and gentamicin (15 mg/ml) are prescribed in instillations under the conjunctiva or parabulbar systemically depending on the severity of the process.

To enhance therapy, instillations are recommended to be performed every 30 minutes during the day and every hour at night for 7-10 days. If there is no effect, the ulcer is extinguished with 10% iodine tincture, mechanical abrasion or diathermocoagulation is performed. In order to prevent iridocyclitis, mydriatic instillations are prescribed. The frequency of their instillation is individual and depends on the severity of inflammatory infiltration and the pupil's reaction.

Steroid drugs are prescribed locally during the period of resorption of inflammatory infiltrates after the surface of the corneal ulcer is epithelialized. At this time, drugs containing a broad-spectrum antibiotic and a glucocorticoid (garazon) are effective. Along with these drugs, inhibitors of proteolysis, immunocorrectors, antihistamines and vitamin preparations are used locally and internally, as well as agents that improve trophism and the process of epithelialization of the cornea (balarpan, taufon, sodcoseryl, actovegin, karpozin, etaden, etc.).

Indications for emergency surgical treatment are progression of the corneal ulcer, 24-36 hours after the start of active treatment - enlargement of the corneal ulcer, folding of the membranes, appearance of daughter infiltrates along the edge of the ulcer. To save the eye, layered therapeutic keratoplasty is performed. The first transplant may melt and fall off - the transplant is done deeper and wider, up to a penetrating transplant of the cornea with the sclera border.

The transplant is done using a cadaveric cornea dried on silica gel.