A marker of target organ damage of hypertension.
Its presence is an indication for initiation antihypertensive treatment.
Retinal changes include arteriolar focal and generalized narrowing, arteriovenous nicking, hemorrhages, cotton-wool spots, and optic disk swelling.
Swelling of the optic disc usually indicates malignant hypertension.
With severe hypertension, raised intracranial pressure and optic nerve ischemia lead to disc swelling, i.e. papilledema.
Prevalence in Framingham study with ophthalmoscopic examination with dilation at 1% and 2-15% with photographic examination of the fundus.
Initial response of retina to elevation in blood pressure is vasospasm seen clinically as generalized retinal arteriolar narrowing.
Chronic atherosclerotic changes subsequently occur with intimal thickening, media wall hyperplasia and hyaline degeneration with changes of diffuse and focal arteriolar narrowing, opacification of arteriolar walls described as silver or copper wiring, and compression of the venules at adventitial locations termed arteriovenous nicking.
As blood pressure increases the blood retinal barrier breaks down with exudation of blood causing hemorrhages, and exudation of lipids causing hard exudates and formation of cotton wool spots which are ischemic nerve fiber layers.
Retinal photography studies reveal hypertensive retinopathy signs present in 2-14% of non-diabetic population.
Blood pressure elevation associated with narrower retinal arteriolar diameters, but does not affect the diameters of veins.
Generalized retinal arteriolar narrowing and arterio-venous nicking reflect current and blood pressure levels of the past and are signs of persistent chronic hypertensive damage.
Focal arteriolar narrowing, retinal hemorrhages, microaneurysms, and cotton wool spots indicate the current state of blood pressure.
Retinal arteriolar narrowing can predict for subsequent hypertension.