Corneal ulcer is a destructive process in the cornea of the eye, accompanied by the formation of a crater–shaped ulcerative defect. Corneal ulcer is accompanied by a pronounced corneal syndrome, pain and a significant decrease in vision of the affected eye, clouding of the cornea. Diagnosis of corneal ulcers is based on data from an eye examination using a slit lamp, an instillation test with fluorescein, bacteriological and cytological examination of scrapings from the conjunctiva, ELISA of tear fluid and blood serum. The principles of treatment of corneal ulcers require specific (antiviral, antibacterial, antifungal, antiparasitic), metabolic, anti-inflammatory, immunomodulatory, hypotensive pharmacotherapy. If there is a threat of perforation of the corneal ulcer, keratoplasty is necessary.
H16.0 Corneal ulcer
The cornea of the eye has a five-layer structure and includes the epithelial layer, Bowman’s shell, stroma, Descemet’s shell and the lower layer of the endothelium. When the epithelium is damaged, corneal erosion occurs. A corneal ulcer is spoken of if the destruction of corneal tissues extends deeper than the Bowman’s shell. Ulcerative lesions of the cornea are among the severe eye lesions in clinical ophthalmology, which are difficult to treat and often lead to significant visual function disorders, up to blindness.
The outcome of corneal ulcers in all cases is the formation of a corneal scar (cataract). The ulcerative defect can be localized in any part of the cornea, but the damage to the central zone is the most severe: it is more difficult to treat, and scarring of this area is always accompanied by loss of vision.
For the development of corneal ulcers, a combination of a number of conditions is necessary: damage to the corneal epithelium, reduction of local resistance, colonization of the defect by infectious agents. Corneal ulcers can have an infectious and non-infectious etiology:
- Infectious factors are represented by herpesvirus, bacterial, fungal, parasitic corneal lesions. From the surface of the corneal ulcer, in most cases, staphylococci, diplococci, streptococci, Pneumococci, Pseudomonas aeruginosa, herpes simplex virus and chickenpox, Mycobacterium tuberculosis, acanthamoeba, fungi, chlamydia are isolated.
- Non-infectious factors may include autoimmune genesis, dry eye syndrome, primary or secondary corneal dystrophy.
Exogenous factors contributing to the development of corneal ulcers include:
- long-term wearing of contact lenses (including the use of contaminated solutions and containers for their storage);
- irrational topical pharmacotherapy with corticosteroids, anesthetics, antibiotics;
- the use of contaminated eye preparations and instruments during therapeutic ophthalmological procedures.
- eye burns,
- foreign bodies getting into the eyes, photophthalmia, mechanical damage to the eyes,
- previously performed surgical interventions on the cornea, etc.
A favorable background for the development of corneal ulcers can be various disorders of the auxiliary apparatus of the eye: conjunctivitis, trachoma, blepharitis, canaliculitis and dacryocystitis, trichiasis, eversion or inversion of the eyelids, lesions of the oculomotor and trigeminal cranial nerves. The danger of corneal ulcers exists in all forms of keratitis (allergic, bacterial, viral, meibomian, neurogenic, filamentous, chlamydial, etc.), as well as non-inflammatory corneal lesions (bullous keratopathy).
In addition to local factors, common diseases and disorders play an important role in the pathogenesis of corneal ulcers: diabetes mellitus, atopic dermatitis, autoimmune diseases (Sjogren’s syndrome, rheumatoid arthritis, polyarthritis nodules, etc.), exhaustion and vitamin deficiency, immunosuppression.
According to the course and depth of the lesion, corneal ulcers are classified into acute and chronic, deep and superficial, impervious and perforated. According to the location of the ulcerative defect, peripheral (marginal), paracentral and central corneal ulcers are distinguished. Depending on the tendency to spread the ulcerative defect in width or depth , they are distinguished:
- Creeping corneal ulcer. It spreads towards one of its edges, while the defect epithelizes from the other edge; at the same time, the ulcer deepens with the involvement of the deep layers of the cornea and iris, the formation of a hypopion. It usually develops against the background of infection with microtrauma of the cornea with pneumococcus, Diplobacillus, Pseudomonas aeruginosa.
- A corrosive ulcer of the cornea. The etiology is unknown; the pathology is characterized by the formation of several peripheral ulcers, which then merge into a single semilunar defect with subsequent scarring.
Among the main, most common clinical forms, corneal ulcers are distinguished:
- infectious (herpesvirus, bacterial, fungal, parasitic, marginal infectious-allergic, trachomatous)
- non-infectious, associated with spring conjunctivitis, systemic immune diseases, dry eye syndrome, primary corneal dystrophy, recurrent corneal erosion.
Symptoms of corneal ulcer
Corneal ulcer, as a rule, has a unilateral localization. The earliest sign signaling the danger of developing corneal ulcers is pain in the eye, which occurs at the stage of erosion and increases with the progression of ulceration. At the same time, a pronounced corneal syndrome develops, accompanied by copious lacrimation, photophobia, edema of the eyelids and blepharospasm, mixed injection of the vessels of the eye.
When the corneal ulcer is located in the central zone, there is a significant decrease in vision due to clouding of the cornea and subsequent scarring of the defect. The scar on the cornea, as the outcome of the ulcerative process, can be expressed to varying degrees – from a delicate scar to a coarse cataract.
The clinic of a creeping corneal ulcer is characterized by severe cutting pains, lacrimation, purulent discharge from the eye, blepharospasm, chemosis, mixed injection of the eyeball. A yellowish-gray infiltrate is detected on the cornea, which, disintegrating, forms a crater-shaped ulcer with regressing and progressive edges. Due to the progressive edge, the ulcer quickly “spreads” across the cornea in width and depth. With the involvement of intraocular structures, the addition of iritis, iridocyclitis, panuveitis, endophthalmitis, panophthalmitis is possible.
With tuberculous corneal ulcer, there is always a primary focus of tuberculosis infection in the body (pulmonary tuberculosis, genital tuberculosis, kidney tuberculosis). In this case, infiltrates with flyctenous rims are found on the cornea, which further progress into rounded ulcers. The course of tuberculous corneal ulcer is prolonged, recurrent, accompanied by the formation of rough corneal scars.
Herpetic ulcers are formed on the site of tree-like infiltrates of the cornea and have an irregular, branched shape. Corneal ulceration caused by vitamin A deficiency (keratomalacia) develops against the background of milky-white opacity of the cornea and is not accompanied by pain. The formation of dry xerotic plaques on the conjunctiva is characteristic. With hypovitaminosis B2, epithelial dystrophy, corneal neovascularization, ulcerative defects develop.
With timely therapeutic measures taken, it is possible to achieve a regression of the corneal ulcer: cleansing its surface, organizing the edges, filling the defect with fibrinous tissue, followed by the formation of scarring – a cataract.
The rapid progression of corneal ulcers can lead to a deepening of the defect, the formation of a descemetocele (hernia-like protrusion of the descemetal membrane), corneal perforation with infringement of the iris in the resulting hole. Scarring of a perforated corneal ulcer is accompanied by the formation of anterior synechiae and goniosynechiae, which prevent the outflow of HCV. Over time, this can lead to the development of secondary glaucoma and optic nerve atrophy.
In the event that the perforation in the cornea is not tampered with by the iris, the purulent infection freely penetrates into the vitreous body, leading to the appearance of endophthalmitis or panophthalmitis. In the most unfavorable cases, the development of orbital phlegmon, cavernous sinus thrombosis, brain abscess, meningitis, sepsis is possible.
To detect corneal ulcers, instrumental diagnostics, special ophthalmological tests and laboratory tests are resorted to. Basic methods:
- Eye examination. The initial examination is performed using a slit lamp (biomicroscopy). The reaction of the deep structures of the eye and their involvement in the inflammatory process are evaluated using diaphanoscopy, gonioscopy, ophthalmoscopy, ultrasound of the eye.
- Investigation of the function of the lacrimal apparatus. During fluorescein instillation, a sign of the presence of a corneal ulcer is the staining of the defect with a bright green color. In this case, the examination allows you to identify even minor corneal ulcers, assess the amount, extent and depth of corneal damage.If necessary, a color tear-nasal test, a Norn test, and a Schirmer test are performed.
- Laboratory tests. To identify the etiological factors that caused the corneal ulcer, cytological and bacteriological examination of the conjunctival smear, determination of immunoglobulins in blood serum and lacrimal fluid, microscopy of scraping from the surface and edges of the corneal ulcer is necessary.
Treatment of corneal ulcer
In case of corneal ulcer, it is necessary to provide specialized inpatient care under the supervision of an ophthalmologist. Treatment includes topical therapy, systemic drug therapy, physiotherapy, and, if necessary, surgical methods.
- Ophthalmological manipulations. In order to prevent the deepening and expansion of the corneal ulcer, the defect is extinguished with an alcoholic solution of brilliant greens or iodine tincture, diathermic or laser coagulation of the ulcerative surface. In case of corneal ulcer caused by dacryocystitis, urgent flushing of the lacrimal-nasal canal or emergency dacryocystorinostomy is necessary to eliminate a purulent focus in close proximity to the cornea.
- Drug therapy. Depending on the etiology of the corneal ulcer, specific (antibacterial, antiviral, antiparasitic, antifungal) therapy is prescribed. Pathogenetic therapy of corneal ulcers includes the appointment of mydriatics, metabolic, anti-inflammatory, antiallergic, immunomodulatory, hypotensive drugs. Medications are administered topically – in the form of instillations, ointment applications, subconjunctival, parabulbar injections, as well as systemically – intramuscularly and intravenously.
- Physical therapy. As the corneal ulcer clears, resorption physiotherapy is prescribed to stimulate reparative processes and prevent the formation of a rough scar: magnetotherapy, electrophoresis, ultraphonophoresis.
- Surgical treatment. With the threat of perforation of the corneal ulcer, through-or layer-by-layer keratoplasty is indicated. After the ulcer heals, excimer laser removal of superficial corneal scars may be required.
Prognosis and prevention
Since the outcome of a corneal ulcer always forms a persistent opacity (a thorn), the prospect for visual function is unfavorable. In the absence of complications, after the inflammation subsides, optical keratoplasty may be required to restore vision. With panophthalmitis and phlegmon of the eye socket, the risk of loss of the organ of vision is high. Fungal, herpetic and other corneal ulcers are difficult to cure and have a recurrent course.
In order to prevent corneal ulcers, it is necessary to avoid microtrauma of the eye, observe the necessary rules when using and storing contact lenses, carry out preventive antibacterial therapy with the threat of infection of the cornea, treat general and eye diseases in the early stages.