RETINAL VASCULAR DISEASES
Hypertensive retinopathy is characterized by retinal vascular derangement caused by severe hypertension. High blood pressure causes both focal and generalized constriction of the retinal arterioles due to autoregulation.
Chronic elevation of arterial blood pressure and degenerative changes in the arteriolar wall manifest ophthalmoscopically as: retinal arterial attenuation, changes in the arteriolar reflex and arteriovenous crossing changes. Increased vascular permeability can lead to retinal lipid deposits (hard exudates) and flame-shaped hemorrhages. The hemodynamic changes in arterial hypertension can lead to vascular occlusion, focal ischemia and nerve fiber layer infarctions (cotton-wool spots).
Acute severe elevation of blood pressure can give rise to hypertensive choroidopathy. Areas of choroidal...