**10. Complementary therapy**

**Figure 13.** Absence of ahypopyon seen in Patient 1 as a manifestation of positive response to antibiotic treatment.

one chosen to continue the treatment for 2-3 more weeks.

Peripheral corneal clearance of infiltrates and density

**Table 9.** Response parameters associated with antibiotic therapy

reduction.

164 Common Eye Infections

Decrease in stromal edema. Less anterior chamber inflammation. Corneal epithelial regeneration.

If clinical improvement exists at 48 hours of initiation of treatment, we encourage to contin‐ ue the same pharmacological agents, reducing the administration time to 1 drop every 2 hours until completion of 5 days with night rest. After the 5 days, if further improvement exists, antibiotic doses should be decreased progressively in function of clinical response, drug tolerance and sensitivity tests results. Antibiotic with the best sensitivity should be the

Special caution should be kept when therapy is suspended, as some microorganisms may

If lesion progression occurs after 48 hours of initiation of treatment, manifested by evident increase in size, stromal thinning or incomplete resolution of symptoms, the ophthalmolo‐ gist should consider a lack of sensitivity to the chosen treatment or a failure in the patient's attachment to the therapy. Culture results should be rechecked as well as sensitivity test re‐

> Increase in size or depth. Stromal thinning.

Partial resolution of symptoms.

remain in corneal tissue. In this case, a prolonged treatment may be required.

sults, as an addition of a different antimicrobial agent might be needed.[Table 9]

**Positive clinical response parameters Negative clinical response parameters**

**Pain management:** The cornea is a highly innervated tissue. Despite most of the times, these lesions tend to have an indolent course, on occasions, patients can refer any degree of pain, ranging from mild to severe. The clinician should administer a cyclopegic agent to ease the symptoms caused by ciliary spasms and to prevent the formation of sinequiae. We recom‐ mend the employment of cyclopentolate 1% eye drops or Atropine 1% collyrium every 12 hours.

**Topical corticosteroids:** Its role and appropriate moment of use is a controversial topic. Cor‐ ticosteroids are applied to diminish the host's inflammatory response, capable of producing tissue destruction. Its use is also aimed to decrease the subsequent corneal cicatrization. Nevertheless, some potential adverse effects of these agents include bacterial growth stimu‐ lation by local immunosuppression, decrease in phagocytic activity, inhibition of collagen synthesis, drug-induced glaucoma and secondary cataract formation. Several experimental studies have shown a lack of harmful effects associated by addition of steroids to the preex‐ istent bactericidal regime in keratitis. However, other studies documented an increase in bacterial growth with the addition of topical steroids to previous therapy. Due to the uncer‐ tain role of these agents in keratitis caused by nontuberculous mycobacteria, we recommend the use of low doses of steroids like fluorometholone (Flumetol® SOPHIA, S.A. de C.V., Laboratorios. Guadalajara, México) if it is considered appropriate, only when certainty ex‐ ists of the infectious process being under control or in an inactive phase.

**Alternate medical treatment:** Authors have recommended the use of Azithromycin 2mg/mL or 1%, prepared Clarithromycin eye drops 10mg/mL, imipenem, tobramycin and systemic doxyciclin. We do not have experience with these drugs. [1,5]

**Surgical treatment Conjunctival flap:** Its purpose is aimed to provide blood vessels to the infected area, thus promoting curation. It is indicated in uncontrolled progression of the cor‐ neal lesion or infiltrates, limbal compromise with imminent scleritis or elevated risk of cor‐ neal perforation.

**Therapeutic penetrating keratoplasty:** It is difficult to perform in the initial stages of myco‐ bacterium keratitis, furthermore it involves a higher incidence of complications and an infe‐ rior graft survival rate in comparison to optical PKP in an inactive process. We recommend to avoid this surgical option when possible. The indications for urgent therapeutic PKP are:


We recommend maximal antibiotic therapy for 48 hours prior to surgery to decrease the number of bacterial colonies as much as possible and consequently the diminish the risk of endophthalmitis. Additional to topical antibiotics, we suggest the use of systemic anti‐ microbial and antiinflammatory agents in the preoperative period. The trepan employed on the recipient's cornea should be of enough size to extract the entire infected area, and the donor's corneal graft should be 0.5mm bigger than the measurement made on the re‐ cipient's cornea. It is advisable to obtain cultures from one half of the obtained cornea tis‐ sue (including stains and special culture media), and the other half should be sent for histopathological study. Sutures should be placed separately due to intense inflammatory reaction. In the postoperative period, corticosteroid therapy should be continued as well as specific antibiotics. Systemic therapy should continue. Posterior to the complete resolu‐ tion of corneal infection, an optical PKP is an option of treatment to seek visual rehabilita‐ tion, as seen in out patient that appears on [Table 7]. As a consequence of the long term infectious process caused by mycobacterium keratitis, secondary cataract formation can be induced by the production of toxins, iridocyclitis, treatment toxicity and corticosteroid us‐ age. For this complication, and optic PKP combined with a cataract extraction and Ahmed valve implantation can be considered as a treatment option, as seen in patient 1 who de‐ veloped glaucoma.[Table 6,7]

**Figure 14.** Patient 1 treated with optic PKP combined with Ahmed valve implantation and cataract extraction with colocation of intraocular lens posterior to the resolution of nontuberculous mycobacterial keratitis.
