The bacteriology and mycology of corneal ulcer

ABSTRACT

The role of predisposing factors in the causation of corneal infection cannot be overemphasized. Noteworthy are the corneal traumatas and local ocular conditions which are either ignored by the patients or are inadequately managedUntreated corneal ulcers are predominantly bacterial (95 percent) while the treated cases are more fungal (61 percent) in etiology. The role of previously considered non-pathogenic organisms in corneal ulcerations should be recognizedFor the purpose of isolating the etiologic organism, specimens for microbiologic studies should be taken from the corneal lesion and should include the advancing borders of the ulcer. A sterile Bard-Parker knife is most efficient for removing the specimen. Conjunctival materials are insufficient for the purpose. When the organism isolated by smear and culture is questionable, a corneal biopsy is indicated especially in mycotic casesCorneal ulcers are generally treated arbitrarily with a variety of topical antibiotic preparations without prior culture and sensitivity studies because either the laboratory facilities are not available or the procedures are costly to the patients. Without such data, management of the infection becomes a matter of shifting from one antibiotic preparation to anotherFailure of the infection to respond favorably to medical treatment is due mainly to either that the drug is given inadequate dosage or it is naturally ineffective against the causative organismPrevention is still the best management of corneal ulcer. This is so because even adequate therapy does not prevent the development of corneal scarring that causes visual impairment. Prophylactic antibiotics, not steroids, must always be given immediately following corneal injuries and the treatment should be closely supervised. Existing local ocular conditions that may be complicated with corneal ulceration should be correctedEffective therapy of corneal ulcers should not only eradicate the infection but also prevent or minimize the degree of corneal scarring and the attendant complications that make corneal transplantation an extremely unrewarding procedure. For medical treatment to be effective, identification of the causative organism and the proper antibiotics is necessary. The drugs must be administered in sufficiently high concentrations topically and by episcleral (sub-Tenons) injection. Treatment and the course of the infection should be closely observed. (Conclusions)