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.
Secondary retinal detachment - also known as exudative retinal detachment or serous retinal detachment. It is caused by inflammation, vascular abnormalities or injury which cause fluid to build up under the retina (there is no hole, break or tear). Tractional retinal detachment - an injury, inflammation or neovascularization causes the fibrovascular tissue to pull the sensory retina from the retinal pigment epithelium.