We report a case of POEMS syndrome in a 20-year-old patient diagnosed after visiting an eye clinic with a chief complaint of reduced visual acuity. A male university student aged 20 years was referred to our department complaining of blurred vision in both eyes that had persisted for 1 month. He also noted headache, nausea, and paresthesia in the lower extremities around the same time. The visual acuity of his right and left eye was 20/40 and 20/20, respectively. Optic disc edema and serous retinal detachment were present. Brain magnetic resonance imaging showed no intracranial abnormalities, while elevated cerebrospinal fluid pressure, reduced nerve conduction velocity in both lower extremities, hepatosplenomegaly, M proteinemia, high blood VEGF levels, osteoblastic and osteolytic changes in the spine, and atypical plasma cells in bone lesions were noted. From the above findings, the patient was diagnosed with POEMS syndrome. He received high-dose dexamethasone, thalidomide, and radiotherapy on the sacral mass, followed by high-dose melphalan with autologous stem-cell support, and showed subsequent systemic and ophthalmologic improvement. Here, we report the youngest case ever of POEMS syndrome with ocular manifestation. If patients have optic disc edema in both eyes with no intracranial space-occupying lesion, POEMS syndrome should be considered in differential diagnosis, regardless of age.