The bacteriology and mycology of corneal ulcer

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)

Freezing in vascularized cornea

As far as we can ascertain in the literature, this is the first time cryogenic procedure has been applied to the difficult problem of obliterating or artificially regressing corneal blood vesselsUtilizing-50 degree celsius we froze a series of 25 cases of vascularized corneas and have carefully and systematically observed clinically the obliteration and complete regression of the blood vessels by the aid of biomicroscope, operating microscope and with the help of intravenous flourescein. Diagrams of the individual vessels were recorded and photographs of various stages of regression were takenHistopathological examinations of the frozen corneal tissues were made. Photomicrographs of the sections showed the death, disintegration, disapperance of the endotholial cells of the blood vesel with extravasation, some inflammatory reaction and complete disappearance of the vessels. The changes in the non-vascular, cellular and non-cellular structures have been shown. Several cases of frozen vascularized cornea have been subjected to keratoplasty after 4 to 5 months with more favorable results than if the corneal freezing had not been done. (Summary)

Anti-collagenases in corneal necrosis

Studies suggest the role of an enzyme with collagenolytic activity in the pathogenesis of corneal necrosis associated with many inflammatory diseases of the cornea. The enzyme is elaborated by the epithelium of both healthy and pathologic corneas, the polymorphonuclear leucocytes and by some micro-organisms like the Pseudomonas aeruginosa. The known anti-collagenase cystein and EDTA which are able to prevent action of the enzyme on reconstituted collagen substrates in-vitro are successfully controlling corneal necrosis and ulceration of bacterial, viral and chemical origin. (Summary)

Fungus infection of the cornea: a review of 43 cases

Forty-three proven cases of fungus infection of the cornea have been studied in the Philippine Eye Research Institute since 1968. Clinical features that suggested the nature of the infection included the (a) history of previous ocular trauma due to some vegetable matter, (b) severity of the pain on the affected eye, (c) non-response to prolonged anti-bacterial therapy, (d) preponderance of hard ulcers indicating minimal tissue necrosis, and the (e) hypopyon, when present, tended to be stringy and well-adherent to the back surface of the corneaEtiologic diagnosis requires demonstration of the organism in smears, cultures or preferably in the biopsy specimens. For this purpose, it is advised that the specimens should include portions of the advancing borders of the lesionsFusarium and Aspergillus which are plant pathogens were the most common fungi isolated from the cases. Others included Mycelia sterila, Hormodendrum, Curvularia, Phialophora verrucosa, Cephalosporium, Paecilomyces and Candida kruseiMedical therapy of the infection was not very encouraging. Part of the reason is that while the antifungal drugs are effective in-vitro against a wide variety of fungal cultures, they poorly penetrate the cornea. Surgical excision of the lesion removed a bulk of the infecting organisms and when used in conjunction with the antimycotic drugs, the procedure helped control the infection. (Summary)

Corneal ulcer: a study of 110 cases

One hundred ten cases of corneal ulcer and abscesses have been analyzedThe role of predisposing factors in the causation of the infection cannot overemphasized. Noteworthy are the corneal traumatas and local ocular diseases which are either ignored by the patients or are inadequately managedCorneal ulcers are predominantly bacterial. Fungi should be suspected in cases that are not responding favorably to anti-bacterial therapy. The role of previously considered non-pathogenic organisms in corneal infection should be recognized. How to deal with sterile corneal ulcer is a problemFor the purpose of isolating the etiologic organisms, specimens for microbiological studies should be taken from the corneal lesions and should include the advancing borders of the ulcer. A sterile Bard-Parker knife is most efficient for this purpose. Conjunctival exudates are insufficient for the purpose. When the organisms isolated by smear or culture is inconclusive, corneal biopsy may be done especially in suspected mycotic infectionsCorneal ulcers are generally treated arbitrarily without benefit of culture and sensitivity studies. This procedure is not without danger. The cost entailed by the procedure is highly warranted in infection that may cause blindnessFailure of the infection to respond favorably to medical treatment is generally due to either that the antibiotic is ineffective against the organism or that the drug is administered in insufficient concentrationsPrevention is still the best management of corneal ulcer. This is so because even adequate therapy does not prevent 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, not only that the organism is identified and the appropriate antibiotics chosen but also that the latter is administered in sufficient concentrations. (Summary and conclusions)

Mindoro blindness from corneal degeneration

The Mindoro corneal blindness is a difficult ophthalmological problem in the Philippines. It is degenerative in nature and familial in tendency, with heredity, nutrition and trauma as probable additional factors. There are no evidences to consider it a part of a dermatological, so-called "lapnus syndrome," and there are insufficient findings to incriminate stored rice as the sole cause of it. It is certainly not due to ariboflavinosis. A small, 6.5 mm., central penetrating corneal transplant may remain transparent for many years in the early cases. For moderately advanced cases, it seems to be the first choice, but for the advanced cases, a wide, 9 mm. or more, penetrating keratoplasty, has been followed by opacification of the graft after about a month. A preliminary wide anterior lamellar grafting needs further trial for those advanced casesThe pathologic picture of degenerative keratopathy may be distinct and pure in the beginning but as the lesion advances, those of inflammation, proliferation, death and even necrosis may appear probably because of biological chain reactionsThe pathogenesis of degenerative keratopathies is probably a disturbance or a defect in one or more parts of the metabolic mechanism which interferes with one or more events in metabolismThe etiology of degenerative keratopathies is often multiple and varies with race, heredity, geography, nutrition and other factorsDegenerative keratopathies should be studied along cellular and non-cellular aspects. (Conclusions)