RT Book, Section A1 Duncan, Jacque L. A1 Parikh, Neeti B. A1 Seitzman, Gerami D. A2 Papadakis, Maxine A. A2 McPhee, Stephen J. A2 Rabow, Michael W. A2 McQuaid, Kenneth R. SR Print(0) ID 1184192124 T1 Infectious Keratitis T2 Current Medical Diagnosis & Treatment 2022 YR 2022 FD 2022 PB McGraw-Hill Education PP New York, NY SN 9781264269389 LK accessmedicine.mhmedical.com/content.aspx?aid=1184192124 RD 2024/03/29 AB Risk factors for bacterial keratitis include contact lens wear—especially overnight wear—and corneal trauma, including refractive surgery. The pathogens most commonly isolated are staphylococci, including MRSA; streptococci; and Pseudomonas aeruginosa, Moraxella species, and other gram-negative bacilli. The cornea has an epithelial defect and an underlying opacity. Hypopyon may be present (eFigure 7–23). Topical fluoroquinolones, such as levofloxacin 0.5%, ofloxacin 0.3%, norfloxacin 0.3%, or ciprofloxacin 0.3%, are commonly used as first-line agents as long as local prevalence of resistant organisms is low (Table 7–2). For severe central ulcers, diagnostic scrapings can be sent for Gram stain and culture. Treatment may include compounded high-concentration topical antibiotic drops applied hourly day and night for at least the first 48 hours. Fourth-generation fluoroquinolones (moxifloxacin 0.5% and gatifloxacin 0.3%) are also frequently used in this setting. Although early adjunctive topical corticosteroid therapy may improve visual outcome, it should be prescribed only by an ophthalmologist.