A 67-year-old woman presented to the emergency department with worsening generalized weakness over the past two weeks. She was diagnosed with a stroke three months ago but had no neurological sequelae. The laboratory findings at the emergency room were as follows: white blood cells, 15,700/µl; hemoglobin, 7.0 g/dL; platelets, 510,000/µl; protein/albumin, 6.5/2.4 g/dL; blood urea nitrogen/creatinine, 98.9/11.4 mg/dL; serum Na+-K+-Cl-, 130-7.0-106 mmol/L; total CO2, 7 mmol/L; C-reactive protein, 28.41 mg/dL. Urinalysis revealed proteinuria (1+) and microscopic hematuria (2+). The patient underwent emergency hemodialysis, and additional serologic tests and a renal biopsy were performed to determine the cause of renal dysfunction. While awaiting the results of these tests, the patient suddenly complained of vision loss in her left eye on the 7th day of hospitalization, and ophthalmologic examination revealed vascular sheathing and retinal hemorrhage (Figure 1). Serologic tests showed normal levels of immunoglobulins and complement, but a positive Myeloperoxidase Anti-Neutrophil Cytoplasmic Antibody (MPO-ANCA). Under suspicion of ANCA vasculitis with ocular involvement, 1000 mg of steroids were initially administered. The following day, the renal biopsy revealed 52% cellular, fibrocellular, and fibrous crescents, 37% global sclerosis along with granuloma formation with giant cells, confirming the diagnosis of ANCA vasculitis, specifically severe Granulomatosis with Polyangiitis (GPA) (Figure 2). The patient was discharged on the 21st day of hospitalization after receiving steroid and cyclophosphamide treatment, with a creatinine level of 2.6 mg/dL and vision restored to 0.8. In ANCA vasculitis, particularly GPA, ocular symptoms are commonly reported in 29-52% of cases, usually presenting as conjunctivitis or retinal vascular disease. However, as seen in this case, ocular involvement in ANCA vasculitis is often overlooked by clinicians until noticeable vision loss occurs. Therefore, in the diagnosis of ANCA vasculitis, it is essential to observe ocular symptoms and conduct a thorough evaluation as part of the systemic assessment.