We present a rare case of a 39-year-old female with extramedullary relapse of acute myeloid leukaemia (AML) isolated to the left eye 2 months post allogeneic haematopoietic stem cell transplant. She initially presented with painless left eye erythema, swelling, and visual impairment. Initial ophthalmology review revealed conjunctival chemosis, raised intraocular pressure, and serous retinal detachments. She was initially treated for suspected orbital cellulitis with intravenous antibiotic and antifungal therapy but clinically progressed so was then treated with intravenous corticosteroids. One week later, she progressed to angle-closure glaucoma with development of a hypopyon and an enlarging subconjunctival mass. She proceeded to urgent subconjunctival biopsy and drainage of subretinal fluid which confirmed extramedullary relapse of AML. Notably, further investigation found no evidence of bone marrow or central nervous system relapse. She proceeded to localized radiotherapy with gradual resolution of the subconjunctival mass and serous retinal detachment and was for consideration of donor lymphocyte infusions and azacitidine therapy; unfortunately, she developed respiratory sepsis and passed away despite maximal efforts. This case represents a rare and unusual presentation of isolated ocular extramedullary relapse of AML and emphasises the importance of early ophthalmology involvement and tissue biopsy when there is high clinical suspicion of the disease.