Treatment of Corneal Ulcer Initially empiric topical broad-spectrum antibiotic therapy More specific antimicrobial therapy directed at the cause Treatment for corneal ulcers, regardless of cause, begins with moxifloxacin 0.5% or gatifloxacin 0.3 to 0.5% for small ulcers and fortified (higher than stock concentration) antibiotic drops, such as tobramycin 15 mg / mL and cefazolin 50 mg / mL, for more significant ulcers, particularly those that are near the center of the cornea.