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 Detachment. Retinal detachment is the result of vitreous liquid (the fluid inside the eye) leaking through a small hole or tear in the retina. When this occurs, the retina slowly peels away from the adjacent tissue, damaging the blood supply to the retina and preventing it from working properly.etinal detachment occurs when the retina separates from the tissue and blood vessels located in the back of the eye. Often brought on by a retinal tear, retinal detachment may lead to permanent vision loss or complete blindness if left untreated.