Conrad Berens Lecture. The management of infectious keratitis as we approach the 21st century.

PURPOSE: To determine the role of cultures in the management of ulcerative keratitis, and to determine the role and selection of either commercially available monotherapy versus combined fortified antibiotics in the treatment of bacterial keratitis.
METHODS: The ocular microbiology files at the Bascom Palmer Eye Institute for the years 1969-1997 were reviewed; as were outpatient data at the Bascom Palmer Eye Institute/Anne Bates Leach Eye Hospital for the 20 years 1978-1997 to arrive at an annual incidence of suspected infectious keratitis. An ulcerative keratitis/management survey of the membership of the Castroviejo Cornea Society in 1995 was also conducted.
RESULTS: For the period 1969-1997, a total of 5,845 eyes were cultured for suspected infectious keratitis. The incidence of keratitis was 3.1 per 1,000 clinic visits. Forty-nine percent of the cultures were positive--82% bacterial isolates, 16% fungal isolates, and 2% parasites. Pseudomonas aeruginosa represented 20% of the bacterial isolates from 1969 through 1997, increasing to 32% and 39% during the two five-year intervals in the decade 1978-1987, and decreasing to 20% during the period 1993-1997.
CONCLUSIONS: 1) Perform corneal scrapings in selected patients with suspected infectious keratitis when risk factors are present, when there is a large central infiltrate, or when empirical therapy has failed. 2) In community/hospital based practice continue to culture all cases of suspected infectious keratitis. 3) Use fortified antibiotics for more severe keratitis. 4) Use monotherapy with a fluoroquinolone and/or other commercially available antibiotics for mild or less suspect keratitis. 5) A third alternative is to combine fortified cefazolin with a fluoroguinolone.