視網膜巨動脈瘤為一種後天性視網膜動脈病變，可導致多層次視網膜出血；其中黃斑部內界膜下出血屬於相對少見之臨床表現。本文報告一位75歲、合併高血壓之女性，因右眼突發性嚴重視力模糊就醫。眼科檢查發現黃斑區有濃厚、舟狀的出血，高度懷疑病灶涵蓋至內界膜下區域。頻譜域光學同調斷層掃描顯示黃斑區呈急峻隆起之高反射性病灶，影像特徵與內界膜下出血一致。患者接受了玻璃體切除手術合併內界膜剝除及內界膜下出血之引流。手術後螢光血管攝影檢查於下顳側動脈發現一搏動性病灶，據此確立黃斑部出血為視網膜巨動脈瘤破裂所致。術後一個月病患視力由術前僅能辨指數進步至6/30，後續頻譜域光學同調斷層掃描之追蹤顯示出血顯著吸收。此病例報告強調對於視網膜巨動脈瘤併發之內界膜下出血，早期辨識及結合影像之診斷策略至關重要；及時施行玻璃體切除手術合併內界膜剝除以清除出血，可加速視力復原、降低血液分解產物對感光細胞之毒性影響，並有助於維持黃斑部功能。

Retinal arterial macroaneurysm (RAM) is an acquired retinal arterial anomaly. Patient with RAM may present with multi-layered retinal hemorrhage; sub–internal limiting membrane (sub-ILM) macular hemorrhage is an unusual presentation of RAM. We report a 75-year-old woman with hypertension who presented with sud-den-onset severe blurred vision in the right eye. Ophthalmic examination revealed a dense boat-shaped macular hemorrhage, suggestive of sub-ILM retinal involvement. Spectral-domain optical coherence tomography (SD-OCT) demonstrated a sharply elevated hyperreflective lesion consistent with sub-ILM hemorrhage. The patient underwent vitrectomy surgery with internal limiting membrane (ILM) peeling and sub-ILM hemorrhage drainage. Postoperative fluorescein angiography demonstrated a pulsatile lesion along the inferotemporal arterial arcade, confirming the macular hemorrhage due to a ruptured retinal arterial macroaneurysm lesion. Visual acuity improved from preoperative counting fingers to 6/30 within one month, and fol-low-up SD-OCT showed marked resolution of hemorrhage. This case highlights the importance of early recognition and imaging-guided diagnosis of sub-ILM hemor-rhage secondary to RAM. Timely surgical evacuation via vitrectomy with ILM peeling can facilitate rapid visual rehabilitation, minimize photoreceptor toxicity, and preserving macular function.