HYPERTENSIVE RETINOPATHY
Hypertensive retinopathy is retinal vascular damage caused by hypertension. Signs usually develop late in the disease. Funduscopic examination shows arteriolar constriction, arteriovenous nicking, vascular wall changes, flame-shaped hemorrhages, cotton-wool spots, yellow hard exudates, and optic disk edema. Treatment is directed at controlling blood pressure and, when vision loss occurs, treating the retina.
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 is a major risk factor for other retinal disorders (eg, retinal artery or vein occlusion, diabetic retinopathy). 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 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
- Hypertensive Retinopathy
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).
Diagnosis is by history (duration and severity of hypertension) and funduscopy.
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.