Pathophysiology of Hypertensive Retinopathy
Acute blood pressure elevation typically causes reversible vasoconstriction in retinal blood vessels, and hypertensive crisis may cause optic disk edema. More prolonged or severe hypertension leads to exudative vascular changes, a consequence of endothelial damage and necrosis. Other changes (eg, arteriole wall thickening, arteriovenous nicking) typically require years of elevated blood pressure to develop. Smoking compounds the adverse effects of hypertensive retinopathy.
Hypertension Hypertension Hypertension is sustained elevation of resting systolic blood pressure (≥ 130 mm Hg), diastolic blood pressure (≥ 80 mm Hg), or both. Hypertension with no known cause (primary; formerly, essential... read more is a major risk factor for other retinal disorders (eg, retinal artery Central Retinal Artery Occlusion and Branch Retinal Artery Occlusion Central retinal artery occlusion occurs when the central retinal artery becomes blocked, usually due to an embolus. It causes sudden, painless, unilateral, and usually severe vision loss. Diagnosis... read more or vein occlusion Central Retinal Vein Occlusion and Branch Retinal Vein Occlusion Central retinal vein occlusion is a blockage of the central retinal vein by a thrombus. It causes painless vision loss, ranging from mild to severe, and usually occurs suddenly. Diagnosis is... read more , diabetic retinopathy Diabetic Retinopathy Manifestations of diabetic retinopathy include microaneurysms, intraretinal hemorrhage, exudates, macular edema, macular ischemia, neovascularization, vitreous hemorrhage, and traction retinal... read more ). Also, hypertension combined with diabetes greatly increases risk of vision loss. Patients with hypertensive retinopathy are at high risk of hypertensive damage to other end organs.
Symptoms and Signs of Hypertensive Retinopathy
Symptoms usually do not develop until late in the disease and include blurred vision or visual field defects.
In the early stages, funduscopy identifies arteriolar constriction, with a decrease in the ratio of the width of the retinal arterioles to the retinal venules.
Chronic, poorly controlled hypertension causes the following:
Permanent arterial narrowing
Arteriovenous crossing abnormalities (arteriovenous nicking)
Arteriosclerosis with moderate vascular wall changes (copper wiring) to more severe vascular wall hyperplasia and thickening (silver wiring)
Sometimes total vascular occlusion occurs. Arteriovenous nicking is a major predisposing factor to the development of a branch retinal vein occlusion.
If acute disease is severe, the following can develop:
Superficial flame-shaped hemorrhages
Small, white, superficial foci of retinal ischemia (cotton-wool spots)
Yellow hard exudates
Optic disk edema
Yellow hard exudates represent intraretinal lipid deposition from leaking retinal vessels. These exudates can develop a star shape within the macula, particularly when hypertension is severe. In severe hypertension, the optic disk becomes congested and edematous (papilledema indicating hypertensive crisis Hypertensive Emergencies A hypertensive emergency is severe hypertension with signs of damage to target organs (primarily the brain, cardiovascular system, and kidneys). Diagnosis is by blood pressure (BP) measurement... read more ).
Diagnosis of Hypertensive Retinopathy
Diagnosis is by history (duration and severity of hypertension) and funduscopy.
Treatment of Hypertensive Retinopathy
Hypertensive retinopathy is managed primarily by controlling hypertension. Other vision-threatening conditions should also be aggressively controlled. If vision loss occurs, treatment of the retinal edema with laser or with intravitreal injection of corticosteroids or antivascular endothelial growth factor drugs (eg, ranibizumab, pegaptanib, bevacizumab) may be useful.
Chronic hypertension progressively damages the retina, causing few or no symptoms until changes are advanced.
Chronic hypertensive retinopathy is recognized by permanent arterial narrowing, arteriovenous crossing abnormalities (arteriovenous nicking), arteriosclerosis with moderate vascular wall changes (copper wiring), or more severe vascular wall hyperplasia and thickening (silver wiring).
Hypertensive crisis can cause retinopathy with superficial flame-shaped hemorrhages; small, white, superficial foci of retinal ischemia (cotton-wool spots); yellow hard exudates; and optic disk edema.
Diagnose patients by history and funduscopy.
Treat primarily by controlling blood pressure, and, for retinal edema, sometimes laser or intravitreal injection of corticosteroids or antivascular endothelial growth factor drugs.