Occur either in the level of subhyaloid space between posterior vitreous face and retina or under internal limiting membrane.
Localized vitreous gel detachment may occur.
Horizontal blood level or boat-shaped hemorrhage is usually apparent, which obscures the underlying retina.
Fluorescein angiography demonstrates blockage of underlying details in areas of hemorrhages.
Underlying causes include retinal tear, bleeding from neovascularization, rupture of the internal limiting membrane, hypertensive retinopathy, posterior vitreous detachment, and vascular occlusion.