**16. Post-operative endophthalmitis: treatment**

tion that affected eyes can benefit from early PPV. Data has shown that there may be differ‐ ence in how diabetic and non-diabetic patients behave with similar endophthalmitis. [53] Generally, diabetic patients having hand movement or better visual acuity obtain vision of 20/40 more often by PPV than after by only vitreous biopsy and the intra-vitreal injection of antibiotics. Type of infecting organism may have prognostic effect on the final visual out‐ come. Due to their ability to induce significant inflammation, Staphylococcus aureus, Strep‐ tococci, and Gram-negative isolates seem to result in a worse visual outcome. [2, 10] Infections with coagulase-negative Staphylococci had final visual acuity of 20/100 or better in the EVS population (84%). Additionally, 80% cases of culture-negative endophthalmitis resulted in a final visual acuity of 20/100 or better. Other strong predictors for poor visual outcome were initial visual acuity of light perception only, older age, corneal ring ulcers, compromised posterior capsule, abnormal intraocular pressure, presence of RAPD, rubeosis iridis, and absence of the red fundus reflex. [51] Benefits of vitrectomy include a better sam‐

ple for cultures, reduction of pathogen load, toxins and inflammatory material.

**15. Endophthalmitis associated with microbial keratitis**

The EVS study recommendations do not apply to late-onset post-operative endophthalmitis, bleb-related endophthalmitis, post-traumatic endophthalmitis and endogenous endophthal‐ mitis. [7, 52] In these circumstances and in the absence of any prospective studies, careful evaluation of each case may be recommended by the treating ophthalmologist. Generally, endophthalmitis in these cases may have more aggressive set of bacterial pathogens and therefore require vitrectomy along with intra-vitreal as well as systemic antibiotics. Al‐ though, the principles of management in cases of post-traumatic and endogenous endoph‐ thalmitis may be the same as for acute post-operative endophthalmitis, the visual outcome is

Many cases of infectious keratitis may progress to endophthalmitis if not treated early in the course of the diseases. [4, 9] Patient with underlying conditions may have propensity to poor response to non-aggressive treatment of infectious keratitis. Infections due to some pathogens may be very difficult to treat in patients with diabetes and other systemic condi‐ tions (Figure 9). Patients with chronic diseases, past history of corneal trauma, cataract sur‐ gery with lack of posterior capsule, having used topical corticosteroids, compromised immune system and trachoma have a poor visual prognosis. The bacterial species include Mycobacterium chelonae, Nocardia species, Staphylococcus aureus, streptococci and Coli‐ forms as well as Capnocytophaga. [3] In these patients, fungi are the most frequently report‐ ed organisms, of which Fusarium species are the commonest. Management in these patients

**14. Limitations of EVS**

186 Common Eye Infections

usually dismal.

According to the EVS, 38% of eyes with post-operative endophthalmitis demonstrated Gram-positive cocci. [10] Since systemically administered antibiotics do not reach sufficient concentrations in vitreous, intravitreal injections have become the accepted primary route of delivery biotic delivery. Desired therapy includes antibiotics which cover most common Gram-positive organisms as well as Gram-negative bacteria. Current protocol includes Gram positive coverage by Vancomycin (1.0 mg/0.1 mL) along with Gram-negative cover‐ age by Ceftazidime (2.25 mg/0.1 mL). If indicated, alternative drugs such as Amikacin (400 ug/0.1 mL), might be considered instead of Ceftazidime. In recent years sensitivity of Gramnegative bacterial species has decreased to the administered Amikacin or Ceftazidime. Po‐ tential alternate of Amikacin and Ceftazidime may include 3rd and 4th generation fluoroquinolones, such as Levofloxacin and Moxifloxacin, with their enhanced activity against Gram-positive pathogens having broad-spectrum activity that covers most organ‐ isms encountered in bacterial endophthalmitis. [54] Anterior chamber levels achieved using Moxifloxacin may be higher than those obtained with any other topically administered fluo‐ roquinolone antibiotics, however, these levels are too low for effective treatment of intraocu‐ lar infections. [55]

Depending on the pharmacokinetics of the drugs selected, intra-vitreal antibiotics may be repeated as needed according to the clinical response at intervals of 48 to 72 hours. The doses selected needs to be appropriate to prevent retinal toxicity. In cases of total vitrecto‐ my, the doses of the intra-vitreal antibiotics are reduced. According to the EVS, systemic antibiotics do not appear to have any effect on the course and outcome of endophthalmitis after cataract surgery. [10] Vancomycin provides a good coverage for Gram-positive bacte‐ ria including Methicillin-resistant Staphylococcus aureus. While, Ceftazidime provides a good coverage for Gram-negative bacteria, Clindamycin, Vancomycin, or Cefuroxime are effective for Propionibacterium acnes endophthalmitis. [3] Anti-inflammatory therapy in the form of corticosteroids at the time of intra-vitreal antibiotics can limit the tissue de‐ struction by infiltrating leukocytes due to their cytokines. Intra-vitreal Dexamethasone in‐ jection (400 mg/0.1 mL) after vitrectomy may lead to a rapid subsidence of the intraocular inflammation. [3]

### **17. Post traumatic endophthalmitis**

The incidence of endophthalmitis after open globe injuries ranges between 2-17% of cases depending on the design of the study and geographical location. [31] For example, a major collective review of 4795 post-traumatic eyes evaluated in 15 tertiary care centers in China over a 5 years period revealed an incidence of 8.4%. [56] In cases of initial evaluation of posttraumatic endophthalmitis, one must exclude presence of an IOFB, as in cases of IOFB, there is much greater risk of developing endophthalmitis than in cases where no IOFB is involved. The incidence of endophthalmitis associated with IOFB may be even higher in the setting of having a ruptured globe in the rural areas as compared with trauma in the urban setting (Figure 10). In the rural areas, the occurrence of post-traumatic endophthalmitis may be as high as 80% after an injury. In contrast, post-traumatic endophthalmitis occurred in 11% of 204 patients in non-rural districts. Depending on the virulent nature of the infecting organ‐ ism, post-traumatic endophthalmitis may occur within hours or several weeks after trauma. [57] In these eyes, the signs of infection usually occur early but may be masked by the posttraumatic reactions of the injured tissue. [58] The initial symptoms are usually pain, intraoc‐ ular inflammation, hypopyon, and vitreous clouding. Risk factors for endophthalmitis after ocular trauma include, delayed presentation, older age, unclean wound, lens capsule rup‐ ture and the presence of IOFB. [31, 57, 59] Appropriate history should be obtained regarding the setting of the trauma and likely nature of the IOFB present. When the fundus view is not possible, imaging studies in the form of ultrasonography and computed tomography should be requested. Magnetic resonance imaging is avoided in cases of suspected metallic IOFBs. Without an imaging study, the IOFB can be missed. To save vision, the IOFB needs prompt removal along-with intra-vitreal antibiotics injections.

Moxifloxacin may be higher than those obtained with any other topically administered fluo‐ roquinolone antibiotics, however, these levels are too low for effective treatment of intraocu‐

Depending on the pharmacokinetics of the drugs selected, intra-vitreal antibiotics may be repeated as needed according to the clinical response at intervals of 48 to 72 hours. The doses selected needs to be appropriate to prevent retinal toxicity. In cases of total vitrecto‐ my, the doses of the intra-vitreal antibiotics are reduced. According to the EVS, systemic antibiotics do not appear to have any effect on the course and outcome of endophthalmitis after cataract surgery. [10] Vancomycin provides a good coverage for Gram-positive bacte‐ ria including Methicillin-resistant Staphylococcus aureus. While, Ceftazidime provides a good coverage for Gram-negative bacteria, Clindamycin, Vancomycin, or Cefuroxime are effective for Propionibacterium acnes endophthalmitis. [3] Anti-inflammatory therapy in the form of corticosteroids at the time of intra-vitreal antibiotics can limit the tissue de‐ struction by infiltrating leukocytes due to their cytokines. Intra-vitreal Dexamethasone in‐ jection (400 mg/0.1 mL) after vitrectomy may lead to a rapid subsidence of the intraocular

The incidence of endophthalmitis after open globe injuries ranges between 2-17% of cases depending on the design of the study and geographical location. [31] For example, a major collective review of 4795 post-traumatic eyes evaluated in 15 tertiary care centers in China over a 5 years period revealed an incidence of 8.4%. [56] In cases of initial evaluation of posttraumatic endophthalmitis, one must exclude presence of an IOFB, as in cases of IOFB, there is much greater risk of developing endophthalmitis than in cases where no IOFB is involved. The incidence of endophthalmitis associated with IOFB may be even higher in the setting of having a ruptured globe in the rural areas as compared with trauma in the urban setting (Figure 10). In the rural areas, the occurrence of post-traumatic endophthalmitis may be as high as 80% after an injury. In contrast, post-traumatic endophthalmitis occurred in 11% of 204 patients in non-rural districts. Depending on the virulent nature of the infecting organ‐ ism, post-traumatic endophthalmitis may occur within hours or several weeks after trauma. [57] In these eyes, the signs of infection usually occur early but may be masked by the posttraumatic reactions of the injured tissue. [58] The initial symptoms are usually pain, intraoc‐ ular inflammation, hypopyon, and vitreous clouding. Risk factors for endophthalmitis after ocular trauma include, delayed presentation, older age, unclean wound, lens capsule rup‐ ture and the presence of IOFB. [31, 57, 59] Appropriate history should be obtained regarding the setting of the trauma and likely nature of the IOFB present. When the fundus view is not possible, imaging studies in the form of ultrasonography and computed tomography should be requested. Magnetic resonance imaging is avoided in cases of suspected metallic IOFBs. Without an imaging study, the IOFB can be missed. To save vision, the IOFB needs prompt

lar infections. [55]

188 Common Eye Infections

inflammation. [3]

**17. Post traumatic endophthalmitis**

removal along-with intra-vitreal antibiotics injections.

**Figure 10.** External photograph of a 63-years-old patient who presented with decreased vision, redness, tearing and pain in his right eye after having trauma several days earlier (a). He was found to have cloudy vitreous and no clear view of the fundus (b). A diagnosis of endophthalmitis was made and patient was treated with intra-vitreal antibiotics after obtaining vitreous biopsy.

Similar to post-operative endophthalmitis, two thirds of the bacteria in post-traumatic en‐ dophthalmitis are Gram-positive and 10% to 15% are Gram-negative. [31] In contrast to post-operative endophthalmitis, virulent Bacillus species are the commonest pathogens in post-traumatic endophthalmitis and can be present in 20% of all cases. In the rural popula‐ tion, they are also found in 42% of cases of post-traumatic endophthalmitis. They are thus the second commonest cause of all cases of endophthalmitis. Most Bacillus infections are as‐ sociated with IOFB. Infections that are caused by Bacillus species usually commence with rapid loss of vision together with severe pain (Figure 11). Bacillus species are resistant to Penicillin and Cephalosporins, but are sensitive to Gentamicin and Vancomycin. Other bac‐ teria include Staphylococcus species, Streptococci, Coliforms, and Clostridium species. [1, 6] Fungi are the causative organisms in 10% to 15% of cases of endophthalmitis after trauma and may occur weeks to months after the trauma. [13]Although mixed microbial infections tend to be less common in post-operative cases of endophthalmitis, they have been isolated in up-to 42% of the trauma-associated endophthalmitis. [1-3]

As compared to post-operative endophthalmitis, the prognosis of post-traumatic endoph‐ thalmitis is usually poor. [28, 31] Poor prognosis stems from the presence of more virulent pathogens, presence of mixed infections, traumatic tissue injury and the failure to start pro‐ phylactic antibiotics. Microbiologic spectrum and visual outcome of culture-positive cases of infectious endophthalmitis after open globe injuries have been presented from two tertiary eye care centers in the Middle East by Al-Omran et al. [59] The most common isolates were coagulase-negative staphylococci and Streptococcus species (26.9% of isolates each). Gramnegative organisms and fungi comprised 12.8% and 3.8% of isolates, respectively. The most common organisms identified were coagulase-negative staphylococci and Streptococcus species. Clinical features associated with better visual acuity outcomes included better pre‐ senting visual acuity, early presentation to the eye clinics, and isolation of a nonvirulent or‐ ganism. Post-traumatic endophthalmitis is associated with a poor visual prognosis.

**Figure 11.** External photographs of a 13-years-old male who presented one week after trauma to his right eye (a and b). He was found to have no light perception vision and evidence of pus filled right eye which required evisceration (c).

### **18. Risks of endophthalmitis with retained IOFB and prevention**

Intraocular penetration of a dirty or soil-contaminated foreign body requires an emergent intervention. Delayed removal of IOFB following trauma may result in a significant increase in the development of clinical endophthalmitis. Risk factors for poor visual outcome may in‐ clude poor initial presenting VA, posterior location of IOFB and the lack of vitrectomy at the time of initial IOFB removal. [27, 28, 59] A retrospective study of a 20-year review found that 8% of patients with an IOFB developed endophthalmitis, of whom half lost all light percep‐ tion. [1, 6] One of the largest study of penetrating eye trauma and retained IOFB in eyes of 565 patients managed at a large tertiary eye care center over a 22 year period revealed that 7.5% of them developed clinical evidence of endophthalmitis at some point after trauma. [31] In these patients, the initial presenting VA of 20/200 or better was recorded in only 18.1% of eyes and the remaining 81.9% had VA ranging from 20/400 to light perception. On‐ ly 25% of these eyes underwent IOFB removal and repair within 24 hours after trauma while 75% had IOFB removal 24 hours or more after trauma. From this group, 70% underwent pri‐ mary PPV at the time of removal of posteriorly located IOFB and only 38.6% had positive cultures. Improvement in vision was only possible in 47.7% of eyes and 38.7% had deteriora‐ tion of their vision, including 22.7% that had complete loss of vision. Predictive factors for the good visual outcome in these patients included good initial presenting VA, early surgi‐ cal intervention to remove IOFB (within 24 hours), and PPV. Predictors of poor visual out‐ come included IOFB removal 48 hours or later, posterior location and no PPV at the time of initial surgery (Figure 12). [31]

**Figure 12.** External photograph of a 43-years-old male who developed post-traumatic endopthalmitis resulting in phthisis of his left eye despite aggressive medical and surgical intervention.

Antibiotic prophylaxis has been advocated for IOFB removal. All patients suspecting of an IOFB should require antibiotic prophylaxis. Beside virulent infections caused by Bacillus species in the setting of IOFB which can cause severe visual loss, Staphylococcus aureus, Coliforms, Streptococci, and, sometimes Clostridium perfringens can also cause sight-threat‐ ening endophthalmitis. [60] If trauma takes place in a rural area, there is more likelihood of infection to be a polymicrobial infection. [27, 28, 31, 59] If the patient presents early with good vision and the IOFB is recognized and treated as soon as possible, then the chances of endophthalmitis are reduced.
