Purpose: We report a case of a 69-year-old female patient who developed a lipid droplet-like foreign body in the anterior chamber 8 months after undergoing phacoemulsification cataract surgery with intraocular lens implantation. Location: Cataract Center, Tianjin Eye Hospital, Tianjin, China. Methods: The lipid droplet was surgically removed from the anterior chamber and sent to Tianjin Medical University School of Pharmacy for analysis, confirming the presence of dexamethasone in the foreign body. Results: The patient experienced a significant decrease in corneal endothelial cell density compared to preoperative levels and her vision remained stable after the removal of the ointment. Conclusion: The presence of tobramycin-dexamethasone ointment in the anterior chamber post-surgery was identified as the primary cause of corneal endothelial cell density loss, attributed mainly to white petroleum and mineral oil. Surgical intervention to remove the ointment from the anterior chamber should be performed promptly. During surgery, mydriasis should be avoided to prevent contamination of the intraocular lens.