Differentiation of premacular hemorrhages with niveau formation

Abstract

W e present three anatomical forms of premacular hemorrhage with niveau formation: hemorrhage in posterior precortical vitreous pocket (intrapocket hemorrhage), sub-internal limiting membrane (ILM) hemorrhage, and premacular retrocortical hemorrhage. Niveau formation is the formation of a horizonal boundary between fluid and blood cells when they accumulate in a closed space, because blood cells with higher specific gravity settle in a standing position. Differentiating between the three forms of hemorrhage is important for understanding the pathophysiology of premacular hemorrhage and selecting treatment. Premacular hemorrhage may cause sudden loss of vision when the accumulation of blood is localized in the macular region. Various causes have been reported, such as retinal arterial macroaneurysm, Valsalva retinopathy, trauma, Terson syndrome, proliferative diabetic retinopathy, retinal vein occlusion, Eales' disease, pregnancy and hematologic disorders [1][2][3][4][5][6][7] . Different treatment approaches have been used, including observation [1] , neodymium-doped yttrium aluminum garnet (Nd:YAG) laser hyaloidotomy or membranotomy [2][3][4][5] , and vitrectomy [6][7] , but no clear guidelines are available. One reason is that the different anatomical forms of premacular hemorrhage are not differentiated before treatment; namely, hemorrhage in the posterior precortical vitreous pocket, hemorrhage behind the ILM, and hemorrhage between the ILM and the posterior vitreous cortex.