PURPOSE: To report the differences between microvascular abnormalities (MVAs) and retinal vasculitis in patients with high myopia (HM) and retinoschisis and discuss the efficacy of treatments, including corticosteroids, and posterior vitreous detachment (PVD). METHODS: We enrolled seven patients with HM retinoschisis in the Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology. Multimodal imaging features of MVAs were examined using ultrawide scanning laser ophthalmoscopy, swept-source optical coherence tomography (SS-OCT), SS-OCT angiography (SS-OCTA), and fundus fluorescein angiography (FFA). Clinical characteristics and responses to corticosteroid therapy and PVD are reported. RESULTS: Multimodal imaging features of MVAs varied with the severity of retinoschisis. Some patients showed no significant MVAs via FFA and SS-OCTA. In the other patients, MVAs were visualized on en-face OCT and SS-OCTA, and fluorescence leakage was observed on FFA, which mimicked retinal vasculitis. MVAs accompanied by paravascular retinoschisis were observed on OCT around the vascular arch, and corticosteroid therapy showed no significant effect. CONCLUSIONS: MVAs in adults with HM differ according to retinoschisis severity. MVAs are distinct from retinal vasculitis and may not be effectively treated with corticosteroids. Vitrectomy-induced or spontaneous PVD may be a better viable therapeutic option for vision-threatening complications in patients with HM. TRANSLATIONAL RELEVANCE: Multimodal imaging features of retinal MVAs in HM retinoschisis are significant for therapeutic options in patients with vision-threatening complications and provide a new research direction for investigating the molecular mechanisms underlying these conditions.