Webster Dictionary(0.00 / 0 votes)Rate this definition: Freebase(0.00 / 0 votes)Rate this definition: Crenulation or Crenulation cleavage is a texture formed in metamorphic rocks such as phyllite, schist and some gneiss by two or more stress directions resulting in superimposed foliations.
Retinal artery occlusion. Retinal artery occlusion is a blockage in one of the small arteries that carry blood to the retina. The retina is a layer of tissue in the back of the eye that is able to sense light. Causes. Retinal arteries may become blocked when a blood clot or fat deposits get stuck in the arteries.
1 Acute PVD: Vitreous hemorrhage in the setting of acute PVD is associated with a retinal tear or break in 70-95% of cases and should invoke an exhaustive search for retinal breaks.  Terson syndrome: Terson syndrome is a rare cause of vitreous hemorrhage associated with subarachnoid hemorrhage.