We report 2 cases of serous macular detachment with intraretinal fluid accumulation that developed 1 day after uneventful phacoemulsification surgery. Because of a dilution error, both eyes received 2 mg/0.1 mL of intracameral cefuroxime at the end of surgery. On postoperative day 1, the corrected distance visual acuity (CDVA) was 20/400 in both eyes. Optical coherence tomography revealed intraretinal fluid accumulation with serous macular detachment, and central foveal thickness measurements were 909 μm and 559 μm in Case 1 and Case 2, respectively. Case 1 responded to systemic acetazolamide, but the condition recurred after cessation of therapy; it then responded to systemic steroid treatment. Case 2 responded to an intravitreal injection of 4 mg of triamcinolone and remained stable throughout the follow-up. The final CDVA was 20/20 in Case 1 and 20/25 in Case 2, and central foveal thickness measurements were 205 μm and 208 μm, respectively.