Corneal ulcer is defined as the erosion in the transparent outer part which is present in front of our eyes. Corneal ulcers may have severe pain and negligence can cause blurred vision or blindness. Corneal ulcers are prominent in people who wear contact lenses in their eyes. Corneal ulcers are the main cause of blindness in the world. Corneal ulcers occur in the centre or at the margins of the cornea. They can vary in sizes and numbers in the cornea. Corneal ulcers are the damage of the epithelium, Bowman’s layer and the stroma of the corneal tissue.
The start of corneal ulcers shows primary symptoms such as intense pain to eyes, redness and watery discharge from the eyes, sensitive eyes (photophobia). Severe symptoms may include blurred vision and blindness. The pain may be inside or around the eyes. Some patients can develop iritis.
To prevent the eyes from damage and cause visual impairment permanently, immediate treatment must be started after the diagnosis. The topical and systemic antibiotics are administered to heal the corneal ulcers. The treatment progresses after the identification of cause of corneal ulcer. If it is due to fungi such as Fusarium, Cephalosporium and Candida, natamycin is administered topically. Topical application of trifluridine drops or vidarabine ointment can help to relieve the corneal ulcers caused by Herpes Simplex type 1 virus. There are chances of the recurrence of viral infections hence topical treatment should be repeatedly given. If the cause of corneal ulcers is bacteria, eyes must not be patched. Patches make the inner part dark and suitable for the bacterial growth. Infection with Pseudomonas aeruginosa is treatedby topically application as well as by subconjunctival injection of gentamicin and polymyxin B. For the infection caused by zoster virus, sulfonamide ointment application is useful.
The prevention measures to avoid the further recurrence of the corneal ulcers must be explained to the patient. Self hygiene and cleaning and wearing properly the contact lenses are the precautionary measures that can be taken.
Corneal ulcers are result of infections by viruses, bacteria, fungi, protozoan or may be caused due to injury to the eye. Bacteria usually causing corneal ulcers are Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus viridians, Streptococcus pneumoniae and Moraxella liquefacians. Viruses which cause corneal ulcers are herpes simplex type-1, variola, vaccinia and zoster viruses.
After the injury to the eye, pathogen can enter and infect the eye through corneal abrasion in the eye. Injury to the eyes and entry of chemicals or toxins in the eye can lead to corneal ulcers without infections. Corneal ulcers caused regardless of injuries are rare. But some pathogens that infect the eye and lead to corneal ulcers are herpes zoster (shingles) and herpes simplex infections.
There are two types of corneal ulcers