Empirical or culture-guided therapy for microbial keratitis? A plea for data.

In the United States, about 30,000 bacterial corneal ulcers are treated annually. Compared with 100, or even 20, years ago ophthalmologists today have available to them many diagnostic tools (including special media and bacterial identification techniques), and in impressive assortment of antibiotics. Many reviews and book chapters describe the uses of microbiologic studies--from Gram and Giemsa staining to media inoculation to immunofluorescence and even molecular genetics--to identify causative organisms. This literature also describes the formulas for preparation of highly concentrated, "fortified" antibiotics for initial treatment of bacterial keratitis, until culture and sensitivity results are available to guide modifications in therapy. It would seem, therefore, that "experts" in the field of corneal and external diseases have reached consensus on an appropriate initial microbiologic evaluation and treatment of suspected microbial keratitis, and the large body of literature on this topic might be considered to represent practice guidelines. It comes as a surprise to many that these published "guidelines" apparently are routinely ignored in current clinical practice.