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.
Central retinal artery occlusion occurs when the central retinal artery becomes blocked, usually due to an embolus. It causes sudden, painless, unilateral, and usually severe vision loss.Diagnosis is by history and characteristic retinal findings on funduscopy.entral retinal artery occlusion occurs when the central retinal artery becomes blocked, usually due to an embolus. It causes sudden, painless, unilateral, and usually severe vision loss.