Keratomalacia is a pathology of the cornea, which is characterized by the formation of foci of necrosis with subsequent melting of the stroma of the cornea. Clinical manifestations include photophobia, lacrimation, edema, eyelid hyperemia, decreased visual acuity, hemeralopia. Diagnosis is reduced to performing biomicroscopy of the eyes, visometry and non-contact tonometry. Conservative therapy involves the use of antibiotics, vitamins and cycloplegics. Surgical treatment is based on end-to-end keratoplasty or keratoprosthetics with implantation of a special prosthesis.
Keratomalacia is a severe lesion of the cornea of the eye associated with a deficiency of vitamin A and protein in the body. Among all corneal pathologies, keratomalacia accounts for 1.7%. The disease is most common in Asia, West Africa and the Middle East, Brazil and Haiti. Currently, the disease is more common in infants who are on artificial feeding. In men and women, corneal lesions are diagnosed with the same frequency.
The etiology remains completely unknown. There is a direct relationship between the development of changes in the cornea and the content of proteins, as well as retinol in the blood. Scientists are studying the effect of changes in clinical and hematological parameters and hemophilic infection on the condition of the cornea of the eyes. To date , the following causes of keratomalacia are distinguished:
- Vitamin A deficiency. Retinol is found in a large number of foods, so in developed countries its primary deficiency is extremely rare. Vitamin A deficiency in the body often develops a second time, which is associated with impaired lipid absorption or damage to the intestinal mucosa.
- Protein starvation. Keratomalacia is most often detected in individuals who adhere to a protein-free or vegetarian diet. Pathology occurs in patients with anorexia, Crohn’s disease, ulcerative colitis, as well as in the postoperative period after gastric resection.
- Pathological changes of the liver. Serum albumin is synthesized in the liver, so the disease can form a second time against the background of lesions of the hepatobiliary system. The main causes are viral hepatitis, cirrhosis of the liver, portal hypertension.
Keratomalacia develops when the total protein in the blood is 3-4 g per 100 ml. A decrease in the albumin-globulin coefficient indicates that it is the low concentration of albumin that plays a more significant role in the occurrence of pathology. It should be noted that the content of albumin in the blood is associated with the functional abilities of the liver.
Initially, the stroma of the cornea is affected. The epithelium gradually peels off above the primary focus. Further, the infiltration sites undergo decay, which causes the subsequent rejection of necrotic tissue. Turbidity is formed for a long time (2-3 months). After the formation of a necrosis zone, the cornea may exfoliate within 1-2 days.
In most cases, the pathology is characterized by a bilateral course. An early symptom of keratomalacia is photophobia. Photophobia may be the only manifestation of the disease for 3-4 months. Even moderate lighting causes severe discomfort. Feeding to protect themselves from the effects of light, patients reflexively close their eyes. Further, lacrimation develops, redness of the eyes and swelling of the eyelids are observed.
Many defects can form on the cornea. With the peripheral location of the defect, visual dysfunction is poorly expressed, patients note a deterioration in vision when the lesion is localized in the central parts. The progression of the disease leads to the fact that the patient sees only the movement of the fingers near the face. Twilight vision with vitamin A deficiency is significantly reduced. Often hemeralopia precedes the appearance of the clinical picture of the disease.
A common consequence of keratomalacia is perforation of the cornea followed by iris prolapse. Patients are at risk of descemetocele formation. Endophthalmitis is considered to be a frequent complication. Inflammation of the internal structures of the eye develops when the infection spreads through a perforation or hematogenically.
Sometimes pathology occurs in the early postoperative period. Patients may have hypopion. The addition of a bacterial infection leads to keratitis. With an unfavorable course of keratomalacia, an extensive staphylomatous thorn is formed, which causes visual dysfunction. There is a possibility of developing subatrophy, less often atrophy of the eyeball.
To make a diagnosis, an anamnesis is collected, a physical examination is performed. Patients may indicate a special diet that they adhere to for a long time. During visual examination, in addition to changes in the cornea, it is possible to detect edema and hyperemia of the eyelids with purulent discharge, injection of bulbar conjunctiva vessels. Special research methods:
- Biomicroscopy of the eye. When viewed with a slit lamp, the appearance of the cornea resembles “frosted glass”. The lesion is usually located in the peripheral parts of the cornea. When the cornea is perforated, the anterior chamber becomes flat. The horizontal level of pus in the chamber area is determined.
- Visometry. Visual acuity at the marginal localization of the defect is not impaired. With the central location of the focus, visual functions decrease until the perception of only “hand movements near the face” or “counting fingers”. After the defect heals, vision improves somewhat, but it does not recover in full.
- Non-contact tonometry of the eye. Measurement of intraocular pressure is a valuable diagnostic method. Keratomalacia is characterized by an increase in IOP, while hypotension of the eye signals perforation. The study is repeated immediately before performing surgery.
Treatment of keratomalacia is carried out on an outpatient basis, with a high risk of perforation of the cornea, hospitalization is indicated. It is important to stick to a diet. The diet should include foods with a high content of protein and vitamin A. Medical treatment is required when a hemophilic bacillus is detected in the scraping from the lesion of the lesion, includes:
- Antibacterial agents. Oral administration of drugs from the group of penicillins and cephalosporins is most effective. Instillations and subconjunctival administration of aminoglycosides are shown. Amphenicols are prescribed only in the form of eye drops.
- Cycloplegics. They are used to dilate the pupil in order to prevent the formation of posterior synechiae. With keratomalacia, there is a high risk of secondary adhesions forming on the background of uveitis. Instillations of drugs from the group of M-cholinolytics are recommended to maintain mydriasis.
- Vitamin therapy. Patients are prescribed vitamin A replacement therapy with mandatory monitoring of its serum levels. It is optimal to conduct 2-3 courses of treatment. Additionally, multivitamin complexes containing B, C and D vitamins are used.
Surgical intervention is necessary in case of deep damage to the layers of the cornea with the risk of formation of a perforation hole or when perforation has already occurred. The main method of treatment is through keratoplasty. The operation is justified with preserved visual functions and the absence of pathological changes on the part of the posterior segment of the eye.
Surgical treatment is often carried out after conservative therapy, since hypopion and infectious eye lesions are among the contraindications. In case of rough vascularization of the eyesore, keratoplasty is limited, in such cases keratoprosthetics with implantation of the Fedorov-Zuev prosthesis and transplantation of the corneal prosthetic complex is justified.
Prognosis and prevention
The outcome of the disease is determined by the severity of the course of keratomalacia. With a small focal damage to the cornea, the prognosis is favorable. The formation of a profusely vascularized eyesore leads to a significant deterioration of vision and is a contraindication to performing keratoplasty, which negatively affects the condition of the visual organ. The most important role is assigned to etiotropic therapy.
Prevention of the development of pathology is reduced to the correction of the diet and the preventive administration of vitamin A. Patients are recommended to undergo a routine examination by an ophthalmologist 2 times a year. Every three months for 2 years after the end of treatment, you need to take a blood test for retinol and perform a proteinogram. If changes are detected, a consultation with a gastroenterologist is indicated.