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 vein occlusions typically occur in older patients with a history of high blood pressure and atherosclerosis. Other causes of retinal vein occlusion include vasculitis, clotting disorders, and medications such as oral contraceptive pills.
Causes of Retinal Hemorrhage in Dogs. 1  Some congenital deformities of the eye predispose the retina to bleeding in the dog, particularly if the defects involve the retinal blood vessels or areas adjacent to the blood vessels. 2  Circulatory disorders that affect blood vessels may also cause retinal hemorrhages. Examples include high blood pressure (hypertension), too much circulating protein in the blood (hyperviscosity syndrome), weakening of the blood vessels from kidney or adrenal gland disease, and sugar diabetes.