**7. Treatment**

Once the suspicion of infectious keratitis has been established, what follows is to lift the flap in the case of LASIK for taking cultures and washing with antibiotics. Some studies have shown that patients in whom this procedure is performed before 3 days after onset of symptoms have a better final visual capacity than those in whom this maneuver takes longer to be done [9, 22, 28].

During scraping, smears for Gram, Lowenstein-Jensen, and Middlebrook stains should be taken [30]. The culture should include media such as blood agar, chocolate, Sabouraud, and thioglycolate, with special emphasis on culture in special media such as Lowenstein-Jensen and Middlebrook in the event that the infection has appeared 7 days or more after surgery, considering atypical bacteria [30]. Culture results reveal that Gram-positive bacteria are the most common organisms present [8].

After taking the culture, it is recommended to wash the interface with fortified vancomycin 50 mg/ml in cases of early onset, and fortified amikacin 35 mg/ml in cases of late onset [30].

In most cases, the cause of the infection is difficult to determine. Among predisposing factor are the history of corneal surgery, excessive intraoperative manipulation, intraoperative contamination, and persistent postoperative epithelial defects of the cornea [7, 35, 36].

The start of empirical treatment is recommended in the case of early symptom onset with fourth-generation fluoroquinolone (after impregnation each 5 min for 30 min) alternated with fortified cefazolin 50 mg/ml every 30 min. In the case of patients who work in hospitals or who have been exposed to hospital environments, cefazolin should be replaced with fortified vancomycin 50 mg/ml due to the risk of methicillin-resistant *Staphylococcus aureus* (MRSA) [30].

In the case of late symptom onset (more than 7 days after surgery), treatment is started with fourth-generation fluoroquinolone (after impregnation) every 30 min, alternating with amikacin 35 mg/ml as well as doxycycline orally 100 mg 2 times a day [30].

Once the empirical treatment is commenced, the result of the stains and culture is expected. The stains are a useful guide, although their specificity and sensitivity may vary depending on the reported microorganism. The positive report of a stain for Gram-positive bacteria has a high sensitivity and a very low specificity, since these bacteria can be present on the ocular surface as normal flora. On the other hand, Gram-negative bacilli have a much higher sensitivity and specificity, and without waiting for culture results we can modify the empirical treatment initiated by replacing cefazolin or vancomycin with fortified ceftazidime [30].

**Figure 3.** *Treatment nomogram.*

*Infectious Keratitis after Surgery DOI: http://dx.doi.org/10.5772/intechopen.113078*

Currently, new treatment modalities have emerged, such as corneal crosslinking, which is an alternative in cases where conventional medical treatment is not sufficient [3, 37]. Corneal crosslinking is highly recommended in patients who have undergone surgery with the SMILE technique [19]. As for antibiotic use, fourth-generation fluoroquinolones are not only a valuable tool in treatment, but are also useful for the prophylaxis of both lamellar and surface refractive procedures, showing superiority in comparison with other antibiotics, such as tobramycin (**Figure 3**) [17].
