Endophthalmitis refers to intraocular inflammation, usually secondary to infection, involving the anterior and posterior chambers of the eye. Presentation commonly involves pain, reduced vision, redness and eyelid swelling. Close inspection with a pen-torch light may reveal corneal clouding, pupil irregularity (ie posterior synechiae) and a hypopyon.
Infectious endophthalmitis can be classified as exogenous if the organism enters from the external environment, and endogenous if the infection enters the eye haematologically from a bacteraemia.
Typically exogenous endophthalmitis occurs following:
- Intraocular surgery (postoperative endophthalmitis) eg phacoemulsification, intravitreal injection. Typically caused by Staphylococcus species, Streptococcus or Gram-negative bacteria. Often presents within 2-5 days of the procedure
- Traumatic globe injury (post-traumatic endophthalmitis). Most commonly secondary to Staphylococcus epidermidis and Bacillus species
- Associated with a thin walled trabeculectomy bleb (bleb-related endophthalmitis). May occur months or years after the original filtration surgery and tends to be due to Streptococcus species and Haemophilus influenza
- Less commonly endophthalmitis can occur secondary to wound (or suture) infections, microbial keratitis and infectious scleritis
All potential cases of endophthalmitis are regarded as an ophthalmic emergency and even delays of several hours can affect the visual prognosis. Diagnosis is confirmed by obtaining intraocular specimens (for culture and microscopy) from both the anterior chamber and vitreous cavity. Intravitreal antibiotics eg amikacin and vancomycin, are the mainstay of treatment and should be administered immediately in any cases of probable endophthalmitis. Management often involves the use of additional agents including mydriatics, intraocular pressure lowering drops and steroids.