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.
The most common cause of retinal detachment is tiny breaks developing inside the retina. The breaks allow the fluid found between the retina and the lens of the eye to leak underneath the retina. A build-up of fluid can cause the retina to pull away from the blood vessels that supply it with blood.