Etiology

Causative organism

• Bacteria: coagulase-negative staphylococci (most common), S. aureus, streptococci, B. cereus (in posttraumatic endophthalmitis)

• Fungi: Candida (most common), mold (Aspergillus, Mucor, and Fusarium species)

Route of entry

• Exogenous (direct inoculation)

  • Intraocular surgeries/injections

    • Postcataract surgery (most common cause of postoperative endophthalmitis)

    • After glaucoma surgery; corneal transplant; intravitreal injections

  • Penetrating trauma (less common)

• Endogenous (hematogenous spread)

  • Presence of a distant infectious focus → bacteremia/fungemia → seeding of the vascular choroid by the organism → spread of infection to the retina and vitreous

An inflammatory reaction to drugs injected into the vitreous

Usually resolves completely without intravitreal antibiotics/vitrectomy