**5. Diagnosis**

The clinical presentation of an infection after refractive surgery comprises decreased visual acuity, secretion, pain, epithelial defect, flap edema, reaction in anterior chamber, ciliary injection, and lacrimation. The signs and symptoms are much more varied in the case of infections by bacteria than by fungi and mycobacteria, where the symptoms can be at first frankly discreet [22].

The time of symptom onset after refractive surgery is one of the most important antecedents associated with the causative microorganism. If the symptoms begin within 7 days after the procedure (early onset), it is more likely that the infection is caused by Gram-positive bacteria or mycobacteria. If the symptoms appear after 7 days of the procedure (late onset) there is a greater likelihood that the causative agent is a mycobacterium, a fungus, Gram-positive bacteria or an *Acanthamoeba* [22–25]. As for *Acanthamoeba* keratitis, it is considered of late-onset and is often not directly related to surgical intervention, but to either the incorrect use of contact lenses or contaminated liquids. It could also occur due to a previous infection. For instance, if surgical interventions such as LASIK are performed on the cornea, intrastromal cysts could be reactivated [26, 27].

For several reasons, bacterial keratitis after refractive surgery presents some variants with respect to infectious infiltrative keratitis not associated with photoablation procedures. In the case of LASIK, it is during the procedure that we take the microorganism to the depth of the corneal stroma and then cover it with the flap. Consequently, an ulcer as such is not observed but rather an abscess below the flap or on the ablated stroma in the case of PRK may appear [28].
