**2. Indications**

The therapeutic keratoplasty is a surgical procedure whose indications include the following circumstances:


Therapeutic Keratoplasty for Microbial Keratitis 13

Fig. 2. The same eye 4 weecks after therapeutic sclerokeratoplasty (Courtesy of Alfredo Gomez Leal,MD Phathology Service of "Asociacion para Evitar la Ceguera en Mexico

Fig. 3. *Mycobacterium chelonae* Keratitis. At initial examination, 4 weeks after penetrating keratoplasty with corneal infiltrates (3.0 X 2.0 mm) withe –gray with irregular and elevated

Other bacterial keratitis that might require a therapeutic keratoplasty are those infections that do not reply to a medical treatment, whose etiological agents grow slowly and behave as opportunists and sluggish and that continue to grow despite the aggressive treatment including crystalline keratopathy caused by alphahemolytic *Streptococcus* Stern GA 1993 The concomitant corneal ulcers are a sequence of severe *gonococcal* conjunctivitis Kawashima M et al 2009 and the ulcer caused atypical mycobacterium, an opportunist pathogen that produce lesions in areas where local resistance is compromised by trauma or prior surgery. Clinically, non-tuberculous *Mycobacteria* cause slow-progressing keratitis, which may mimic the indolent course of disease caused by others organism as fungi or anaerobic bacteria and frequently an delayed diagnosis progress to a severe keratitis Perez-Balbuena et al, 2010.

Hospital "Dr. Luis Sanchez Bulnes")

edges in the donor-receptor interface.

Figs. 3, 4, 5

The Therapeutic keratoplasty is an emergency in which the integrity of the ocular globe is at risk, contrary to the optical keratoplasty where the visual rehab is indicated after the process is already controlled.

Infectious keratitis present different clinical characteristics and history, depending on its etiology: therefore, the situations which require a penetrating keratoplasty are different from the bacterial micotic keratitis or for the *Acanthamoeba.* 

### **2.1 Bacterial keratitis**

The impact of bacterial keratitis on corneal blindness for scars, or other ocular complications is very important. In undeveloping countries for traumas risk, or in developed coutries in contact lens users, bacterial keratitis is a leading cause of corneal blindness.

Probably, the first indication for therapeutic keratoplasty, within the perforated corneal ulcers whose etiological agent is *Psedomonas aeruginosa*, especially in tropical climates, in contact lens users and in hospitalized or weak patients.

*Psedomonas aeruginosa* typically present as a rapidly evolving suppurative stromal infiltrate with marked mucopurulent exudate and become to corneal perforation in 24 to 48 hours because P *aeruginosa* due to colagenase production causing an important corneal stroma loss. Therapeutic keratoplasty is required too in corneal ulcers caused by others Gram negative bacteria as *Enterobacter*, *Serratia, klebsiella and Escherichia* that contaminate contact lens and cause a severe corneal desepitelization and ulcers with a great damage of corneal stroma with marked mucopurulent exudate frequently with similar characteristics of progressive suppurative keratitis. Fig 1,2

According to a survey published in 2007 by Ti et al, out of a revision of 92 patients (1991 to 2002) with acute infectious Keratitis in Singapore National Eye Centre, reported the *Pseudomonas aeruginosa* as the main etiological agent, responsible for the keratitis requiring therapeutic keratoplasty.

Fig. 1. Corneal ulcer caused by Gram negative, with perforation and poor response to medical treatment.

The Therapeutic keratoplasty is an emergency in which the integrity of the ocular globe is at risk, contrary to the optical keratoplasty where the visual rehab is indicated after the process

Infectious keratitis present different clinical characteristics and history, depending on its etiology: therefore, the situations which require a penetrating keratoplasty are different

The impact of bacterial keratitis on corneal blindness for scars, or other ocular complications is very important. In undeveloping countries for traumas risk, or in developed coutries in

Probably, the first indication for therapeutic keratoplasty, within the perforated corneal ulcers whose etiological agent is *Psedomonas aeruginosa*, especially in tropical climates, in

*Psedomonas aeruginosa* typically present as a rapidly evolving suppurative stromal infiltrate with marked mucopurulent exudate and become to corneal perforation in 24 to 48 hours because P *aeruginosa* due to colagenase production causing an important corneal stroma loss. Therapeutic keratoplasty is required too in corneal ulcers caused by others Gram negative bacteria as *Enterobacter*, *Serratia, klebsiella and Escherichia* that contaminate contact lens and cause a severe corneal desepitelization and ulcers with a great damage of corneal stroma with marked mucopurulent exudate frequently with similar characteristics of

According to a survey published in 2007 by Ti et al, out of a revision of 92 patients (1991 to 2002) with acute infectious Keratitis in Singapore National Eye Centre, reported the *Pseudomonas aeruginosa* as the main etiological agent, responsible for the keratitis requiring

Fig. 1. Corneal ulcer caused by Gram negative, with perforation and poor response to

contact lens users, bacterial keratitis is a leading cause of corneal blindness.

from the bacterial micotic keratitis or for the *Acanthamoeba.* 

contact lens users and in hospitalized or weak patients.

progressive suppurative keratitis. Fig 1,2

therapeutic keratoplasty.

medical treatment.

is already controlled.

**2.1 Bacterial keratitis** 

Fig. 2. The same eye 4 weecks after therapeutic sclerokeratoplasty (Courtesy of Alfredo Gomez Leal,MD Phathology Service of "Asociacion para Evitar la Ceguera en Mexico Hospital "Dr. Luis Sanchez Bulnes")

Other bacterial keratitis that might require a therapeutic keratoplasty are those infections that do not reply to a medical treatment, whose etiological agents grow slowly and behave as opportunists and sluggish and that continue to grow despite the aggressive treatment including crystalline keratopathy caused by alphahemolytic *Streptococcus* Stern GA 1993 The concomitant corneal ulcers are a sequence of severe *gonococcal* conjunctivitis Kawashima M et al 2009 and the ulcer caused atypical mycobacterium, an opportunist pathogen that produce lesions in areas where local resistance is compromised by trauma or prior surgery. Clinically, non-tuberculous *Mycobacteria* cause slow-progressing keratitis, which may mimic the indolent course of disease caused by others organism as fungi or anaerobic bacteria and frequently an delayed diagnosis progress to a severe keratitis Perez-Balbuena et al, 2010. Figs. 3, 4, 5

Fig. 3. *Mycobacterium chelonae* Keratitis. At initial examination, 4 weeks after penetrating keratoplasty with corneal infiltrates (3.0 X 2.0 mm) withe –gray with irregular and elevated edges in the donor-receptor interface.

Therapeutic Keratoplasty for Microbial Keratitis 15

positive bacteria in 67.2% cases, Gram negative bacteria in 14.91%, and fungal keratitis in 6.81% cases; In my Service, I found in 3240 keratoplasties from 2000-2010, 3.30% patients

needed therapeutic keratoplasty. Figs. 6, 7

Fig. 6. Fungal keratitis (*fusarium solani*) 4 weeks evolution.

Fig. 7. Septated hyphal cells from *Fusarium solani* (Schiff stain 100X)

intervention (92.4% in 1995 vs. 100.0% in 2005; p=0.005).

**2.2 Fungal keratitis** 

With the upcoming of new and more powerful antibiotics (fourth generation quinolones), the therapeutic keratoplasty is less frequently required for keratitis caused by Gram positive bacteria Al-Shehn et al. 2009, highlighted this over a 10-year period (1995-2005). They noted significant improvement in percentage of eyes achieving microbiological cure with medical therapy alone (76.0% in 1995 vs. 92.2% in 2005; p=0.002) or combining with surgical

The therapeutic keratoplasty has an important role in the refractory mycotic ulcers treatment. In a series published by Ibrahim MM et al in 2009 in Brasil, 66 patients with

Fig. 4. Successful therapy 2 months with after topical Gatifloxacin 0.3% therapy.

Fig. 5. Eighteen months after therapy discontinuation, corneal graft is infection–free and clear in the visual axis.

Mycobacterium keratitis is frequently present after a surgical procedure like refractive surgery (LASIK) with a slow progression to need a flap amputation or a therapeutic keratoplasty Susiyanti M, et al 2007.

Critical corneal infections occasionally requires conjunctival flap or therapeutic keratoplasty, in USA eye banking statistics identify microbial keratitis as a reason for keratoplasty in 1% of all corneal transplantation and in relation to bacterial keratitis incidence approximately 1% of USA cases of corneal infections become surgical candidates. Wilhelmus KR. 1998

In the experience obtained at the cornea service of "Dr. Luis Sánchez Bulnes" Hospital in Mexico, reported 2025 cases of infectious keratitis (survey carried out by fellow Carlos Johnson Villalobos MD. In a period from 2001 thru 2010, the causative agents were Gram

Fig. 4. Successful therapy 2 months with after topical Gatifloxacin 0.3% therapy.

Fig. 5. Eighteen months after therapy discontinuation, corneal graft is infection–free and

Mycobacterium keratitis is frequently present after a surgical procedure like refractive surgery (LASIK) with a slow progression to need a flap amputation or a therapeutic

Critical corneal infections occasionally requires conjunctival flap or therapeutic keratoplasty, in USA eye banking statistics identify microbial keratitis as a reason for keratoplasty in 1% of all corneal transplantation and in relation to bacterial keratitis incidence approximately 1% of USA cases of corneal infections become surgical candidates. Wilhelmus KR. 1998 In the experience obtained at the cornea service of "Dr. Luis Sánchez Bulnes" Hospital in Mexico, reported 2025 cases of infectious keratitis (survey carried out by fellow Carlos Johnson Villalobos MD. In a period from 2001 thru 2010, the causative agents were Gram

clear in the visual axis.

keratoplasty Susiyanti M, et al 2007.

positive bacteria in 67.2% cases, Gram negative bacteria in 14.91%, and fungal keratitis in 6.81% cases; In my Service, I found in 3240 keratoplasties from 2000-2010, 3.30% patients needed therapeutic keratoplasty. Figs. 6, 7

Fig. 6. Fungal keratitis (*fusarium solani*) 4 weeks evolution.

Fig. 7. Septated hyphal cells from *Fusarium solani* (Schiff stain 100X)

With the upcoming of new and more powerful antibiotics (fourth generation quinolones), the therapeutic keratoplasty is less frequently required for keratitis caused by Gram positive bacteria Al-Shehn et al. 2009, highlighted this over a 10-year period (1995-2005). They noted significant improvement in percentage of eyes achieving microbiological cure with medical therapy alone (76.0% in 1995 vs. 92.2% in 2005; p=0.002) or combining with surgical intervention (92.4% in 1995 vs. 100.0% in 2005; p=0.005).
