Snapshot A 70-year-old woman presents to the emergency department for severe pain and redness of her left eye for the past day. She underwent left eye cataract surgery approximately 1 week ago. Over the past few days, her ocular pain has progressively worsened and her vision has deteriorated in her left eye. Ophthalmology was consulted and performed a dilated fundus examination, noting findings of conjunctival redness, hypopyon, and vitreous opacities. A vitreous sample is obtained and she undergoes intravitreal administration of vancomycin, ceftazidime, and voriconazole. INTRODUCTION Endophthalmitis is an inflammation of the intraocular fluids, usually due to bacterial or fungal infection. Diagnosis is made on the basis of clinical features, including eye pain, decreased visual acuity, diffuse bulbar conjunctival hyperemia, hypopyon, and signs of intraocular inflammation. Treatment consists of intravitreal injection of antimicrobials. Epidemiology incidence varies according to etiology post-cataract surgery endophthalmitis incidence is 0.04 to 0.1% post-bleb surgery endophthalmitis incidence is 0.06 to 13.2% incidence of endogenous cases due to bacteremia is around 0.05% risk factors ocular trauma eye surgery keratitis extending into the eye systemic infection ETIOLOGY Pathophysiology exogenous endophthalmitis results from inoculation of bacteria or fungal organisms intraocularly from outside the eye causes may include the following ocular trauma eye surgery extension of corneal infection endogenous endophthalmitis results from bacterial seeding of the eye in the setting of bacteremia or fungemia Presentation Symptoms eye pain blurred vision redness of the eye Physical exam conjunctival injection and edema hypopyon settling of inflammatory infiltrate in the anterior chamber vitreous opacities or haze sign of intraocular inflammation causes poor visualization of the retina IMAGING Ultrasound evaluation indications should be performed if adequate view of the fundus is compromised findings vitritis Studies Serum labs blood culture Invasive studies needle aspiration samples of the aqueous and vitreous fluid for culture Differential Anterior uveitis key differentiating factors far fewer inflammatory cells and debris in the anterior and posterior chambers compared to endophthalmitis can be treated effectively with topical steroids Treatment Medical intravitreal antibiotics indication first-line treatment for bacterial endophthalmitis medications vancomycin with ceftazidime or amikacin intravitreal antifungals indication first-line treatment for fungal endophthalmitis medications voriconazole or amphotericin Surgical pars plana vitrectomy indication patients presenting with light perception-only visual acuity higher chance of vision improvement in these patients with immediate vitrectomy compared to fluid tap and injection of intravitreal antibiotics severe or rapidly worsening endophthalmitis Complications Blindness Prognosis vision-threatening emergency can lead to blindness if not promptly treated visual acuity of light perception-only at presentation portends poor prognosis