Fortified preparations of ophthalmic antibiotics are made with commercially available antibiotics (parenteral or lyophilized preparations). These fortified eyedrops have two main advantages: the increase in the antibiotic concentration in the corneal stroma and the wide choice of available antibiotics. Fortified ophthalmic solutions are used in severe keratitis (large diameter, stroma infiltration, inflammation of the anterior chamber, old patient). The following associations are recommended: ticarcillin+gentamicin+vancomycin or cephazolin+amikacin since they provide a broad-spectrum antibiotic activity against the wide range of bacteria that may cause keratitis. The main toxicity of these preparations is the retardation effect of the epithelial-healing rate (aminoglycosides, vancomycin) and the corneal and conjunctival toxic effects (aminoglycosides). However, fortified antibiotic drops remain the standard therapy for severe bacterial keratitis, given their corneal penetration and the possibility of the synergic and combined effect of an antibiotic association.