**13. Endophthalmitis vitrectomy study (EVS)**

Endophthalmitis Vitrectomy Study, a multicenter randomized prospective clinical trial of 420 patients with acute post-operative endophthalmitis, showed that immediate PPV pro‐ vided a clear benefit in a well defined subgroup; patients with light perception vision only at the time of presentation had a significant, 3-fold improved chance of obtaining 20/40 vi‐

trectomy is that adequate material for culturing the causative organism can be obtained be‐

**Figure 7.** An elderly male patient presented with right eye pain, redness and photophobia (a), which was attributed to delayed onset post-operative endophthalmitis requiring intervention (b). After treatment of intraocular infection,

Bleb-related endophthalmitis usually follows a chronic course of infection (Figure 8). In these infections, commonest causative organisms are Streptococcus species and Gram-nega‐ tive bacteria, especially Haemophilus influenzae. [29] Because of the existing history of glau‐ coma, visual prognosis in these cases is expected to be poor requiring early aggressive intervention. [3] These patients require immediate vitrectomy along with intra-vitreal antibi‐ otic injection. These patients may also require systemic antibiotics. Most frequent causative organisms isolated in cases of delayed-onset bleb-related endophthalmitis include, Strepto‐ coccus species, Enterococcus and Gram-negative bacteria. [29] A retrospective consecutive case series of delayed-onset bleb-associated endophthalmitis seen at Bascom Palmer Eye In‐ stitute over a 14 year period identified 86 eyes of 85 patients from which 63% eyes were cul‐ ture-positive. [50] The most common organisms recovered from cultures among these patients were: Streptococcus, 25%; Gram-negative, 18%; coagulase-negative Staphylococcus, 11%; Enterococcus, 7%; Moraxella, 10%; Pseudomonas, 4%; and Serratia, 4%. This large study revealed that culture-positive cases were associated with worse presenting visual acuity, higher presenting intraocular pressure, and worse visual outcomes than culture-neg‐ ative cases. Streptococcus, Pseudomonas, and Serratia cases were associated with poor pre‐ senting view of the fundus and worse visual outcomes than coagulase-negative Staphylococcus and Moraxella cases. [50] Worse view of the fundus in the Streptococcus cas‐

sides obtaining of the capsular bag material as well. [3]

patient's symptoms improved (c).

184 Common Eye Infections

**12. Bleb-related endophthalmitis**

(a) (b) (c)

es likely compelled the treating clinician to more frequently favor PPV.

Endophthalmitis Vitrectomy Study, a multicenter randomized prospective clinical trial of 420 patients with acute post-operative endophthalmitis, showed that immediate PPV pro‐ vided a clear benefit in a well defined subgroup; patients with light perception vision only at the time of presentation had a significant, 3-fold improved chance of obtaining 20/40 vi‐

**13. Endophthalmitis vitrectomy study (EVS)**

**Figure 8.** External (a), slit-lamp (b) and fundus (c) photographs of a patient who developed bleb-related endophthal‐ mitis which was treated with topical and intra-vitreal antibiotics resulting in resolution of infection as evident by exter‐ nal (d,e) and fundus photograph (f).

sion or better after PPV. [10] For diabetic patients with hand movement or better vision, at least a trend toward better final VA after PPV was documented compared with vitreous tap and biopsy only. Patients with diabetes had a trend toward worse vision at baseline, higher incidence of positive cultures and need for additional surgeries and worse final visual out‐ come. [33, 51, 52] According to the EVS recommendations, patients with acute post-opera‐ tive endophthalmitis after a cataract operation with an initial vision of hand movements or better can be treated by vitreous biopsy and intra-vitreal antibiotics. [10] On the other hand patients having vision at presentation worse than hand movement should undergo immedi‐ ate PPV. Further, patients with suspected aggressive pathogens such as acute Streptococcal endophthalmitis, immediate PPV may be necessary even though vision is better than light perception at their initial presentation. Immediate PPV can remove the highly inflammatory bacterial pathogens from the vitreous cavity. Retrospective studies have confirmed this no‐ 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.
