**5. Risk factors for the development of the post-operative endophthalmitis**

The relative risks of developing post-operative endophthalmitis depend on a number of fac‐ tors, including the presence of eyelid or conjunctival diseases, the patient's general health, the use of immunosuppressant medications, the type of intraocular surgery, the type of intra-ocu‐ lar lens (IOL) used and intra-operative complications. [31] Diabetes has been associated with endophthalmitis; one study revealed that among the 162 patients who were treated for en‐ dophthalmitis, 21% of them had evidence of diabetes. In that study, patients with diabetes had poor visual outcome and the possibility was related to these patient's having poor wound healing ability. This association was also observed in the EVS trial, patients with diabetes had a trend toward worse vision at baseline, higher incidence of positive cultures and need for ad‐ ditional surgeries during follow-up. [33] Specific eyelid or peri-orbital diseases such as ble‐ pharitis, ectropion, entropion and paralytic disorders may enhance the chance of postoperative endophthalmitis. It is recommended that minimizing the contact between IOL and the ocular surface may reduce the risk of endophthalmitis at the time of its implantation. Risk of developing endophthalmitis has been reported to be lower with the introduction of injecta‐ ble IOLs as compared with foldable lenses since injectable lenses avoid the contact with ocu‐ lar surface. There is also evidence that certain kinds of materials used for manufacturing intraocular lenses may have higher incidence of endophthalmitis. For example, PMMA lens‐ es may be associated with a higher rate of endophthalmitis as compared with acrylic IOLs. [5, 34, 35] Intra-operative complications, specifically posterior capsular break or vitreous loss may also be a cause of increased risk of post-operative endophthalmitis.

after cataract surgery in which case the patient may present with swollen eyelid, opaque cor‐ nea, conjunctival chemosis and significant pain. [2, 3] Endophthalmitis elicits an aggressive inflammatory reaction that can result in the breakdown of the blood-ocular barrier. Such acute inflammatory process may need to be controlled in order to preserve vision by protecting the uveal tissue. Intra-vitreal Dexamethasone at the time of vitreal biopsy and intra-vitreal antibi‐

**Figure 4.** External photograph of a patient's right eye who presented with decreased vision, pain, tearing, redness and photophobia several days after having penetrating trauma to his right eye. He was found to have conjunctival chemosis along with anterior chamber hypopyon (a). Ultrasonography revealed evidence of vitreous opacification

**5. Risk factors for the development of the post-operative endophthalmitis**

The relative risks of developing post-operative endophthalmitis depend on a number of fac‐ tors, including the presence of eyelid or conjunctival diseases, the patient's general health, the use of immunosuppressant medications, the type of intraocular surgery, the type of intra-ocu‐ lar lens (IOL) used and intra-operative complications. [31] Diabetes has been associated with endophthalmitis; one study revealed that among the 162 patients who were treated for en‐ dophthalmitis, 21% of them had evidence of diabetes. In that study, patients with diabetes had poor visual outcome and the possibility was related to these patient's having poor wound healing ability. This association was also observed in the EVS trial, patients with diabetes had a trend toward worse vision at baseline, higher incidence of positive cultures and need for ad‐ ditional surgeries during follow-up. [33] Specific eyelid or peri-orbital diseases such as ble‐ pharitis, ectropion, entropion and paralytic disorders may enhance the chance of postoperative endophthalmitis. It is recommended that minimizing the contact between IOL and the ocular surface may reduce the risk of endophthalmitis at the time of its implantation. Risk of developing endophthalmitis has been reported to be lower with the introduction of injecta‐ ble IOLs as compared with foldable lenses since injectable lenses avoid the contact with ocu‐ lar surface. There is also evidence that certain kinds of materials used for manufacturing intraocular lenses may have higher incidence of endophthalmitis. For example, PMMA lens‐ es may be associated with a higher rate of endophthalmitis as compared with acrylic IOLs. [5,

otics has been found to be very helpful in minimizing uveal tissue damage.

(a) (b)

suggestive of endophthalmitis (b).

178 Common Eye Infections

**Figure 5.** External photograph of a patient's left eye showing failed corneal graft due to infectious keratitis and en‐ dophthalmitis.

Procedures, such as penetrating keratoplasty, trabeculectomy, and glaucoma drainage de‐ vice implantation have all been reported to cause endophthalmitis which are higher than simple cataract operation (Figure 5). [36] Endophthalmitis can occur in 0.2-9.6% of cases fol‐ lowing glaucoma surgery depending on the procedure and the use of 5-fluorouracil or mito‐ mycin-C as anti-fibrotic agents. [3, 29, 30] Rare causes of endophthalmitis have been reported following phakic IOL implantation for refractive errors and extra-ocular surgeries such as excision of pterygium, strabismus surgery and sclera buckling procedure. [4] Secon‐ dary IOL implantation has been found to be associated with the highest risk for developing endophthalmitis (0.2%–0.37%) and PPV with the lowest (0.03%–0.05%). Other sources of in‐ fection include, contaminated surgical equipment, irrigation fluids and poor patient hy‐ giene. Other risk factors for the development of post-operative endophthalmitis include canaliculitis, acute and chronic dacryocystitis and anti-glaucoma aqueous drainage devices. [36-39] It is recommended that patient having any evidence of chronic canaliculitis, dacryo‐ cystitis should only undergo any intraocular surgery after resolution of their infection. Pa‐ tients having chronic dacryocystitis may harbor multiple micro-organisms which may be resistant to the commonly prescribed post-cataract surgery prophylactic antibiotics. It has been reported that almost 10% of patients having chronic dacryocystitis in the setting of na‐ solacrimal duct obstruction may develop acute dacryocystitis requiring systemic antibiotics. [37-39]
