Abstract: Intraocular foreign body residue following ophthalmic surgery is rare but may cause severe postoperative occult inflammation. In some cases, small foreign bodies located in the anterior chamber angle may be missed by follow-up ultrasound biomicroscopy (UBM). We report the case of an elderly female whose right eye was injured by a nail and received corneal repair surgery in our hospital. Eleven days post-surgery, we found a mobile, short, translucent, rod-shaped foreign body in the upper corner of the right eye and another in the iris root at 7 o’clock. Two months post-surgery, the patient consulted a doctor due to right eye redness, pain, and vision loss, which was ultimately shown to be associated with foreign body residue resulting in a delayed postoperative inflammatory response. The patient was cured by surgeries and active anti-inflammatory and anti-infection treatments, but the final diagnosis of the patient was infectious endophthalmitis misdiagnosed as uveitis, which worths our consideration. We also review relevant literature on the differentiation of postoperative infectious endophthalmitis from noninfectious uveitis. It’s a reminder that patients with delayed endophthalmitis after open ocular trauma should not exclude the possibility of intraocular foreign bodies. As well clinicians can distinguish infectious endophthalmitis from uveitis by needle aspiration biopsy or vitrectomy for microbial culture in order to determine the need for antibiotic treatment.