Bacterial endophthalmitis describes inflammation of the vitreous secondary to bacterial colonisation. It is an ophthalmic emergency requiring prompt treatment to increase the chance of preserving sight and saving the eye. It is categorised as exogenous or endogenous in origin. Endogenous bacterial endophthalmitis is rare, resulting from the haematogenous spread of bacteria from systemic infection. Exogenous bacterial endophthalmitis, however, results from the introduction of bacteria from the ocular surface or an external source into the eye. This can occur post-operatively, following a penetrating ocular trauma, or after an intra-ocular procedure such as intravitreal injections.