Hypertension and Eye Damage

Study Notes

Hypertension is a risk factor for systemic conditions that can lead to target-organ damage, including ocular effects such as retinopathy, optic neuropathy, and choroidopathy.
Hypertension can cause occlusion of major retinal vessels, including the branch retinal artery, central retinal artery, branch retinal vein, and central retinal vein.

Hypertensive retinopathy is the most common ocular presentation of hypertension.
The disease is caused by chronically elevated blood pressure, defined as SBP > 140 mmHg and DBP > 90 mmHg.
Hypertensive retinopathy includes two disease processes: acute effects of systemic arterial hypertension and chronic effects of hypertension.
The acute effects result from vasospasm to autoregulate perfusion, while the chronic effects are caused by arteriosclerosis and predispose patients to visual loss.

In the United States, 33% of adults have hypertension, but only 52% have controlled blood pressures.
The prevalence of hypertensive retinopathy ranges from 2-17% in non-diabetic patients, varying by demographic groups.
The disease is more common in African Americans and those of Chinese descent.
Incidence of blood pressure increases with age, with men more affected than women in age groups < 45 years old, and women more affected in age groups > 65 years old.

Primary hypertension is usually essential and not secondary to another disease process.
Essential hypertension is a polygenic disease with multiple modifiable environmental factors contributing to the disease.
Secondary hypertension can develop in the setting of various underlying diseases, such as pheochromocytoma, primary hyperaldosteronism, and others.

Risk factors for essential hypertension include high salt diet, obesity, tobacco use, alcohol, family history, stress, and ethnic background.
The major risk for arteriosclerotic hypertensive retinopathy is the duration of elevated blood pressure.
The major risk factor for malignant hypertension is the degree of blood pressure elevation over normal.

Hypertensive retinopathy goes through vasoconstrictive, sclerotic, and exudative phases based upon the extent of hypertension control.
In the vasoconstrictive phase, local autoregulatory mechanisms cause retinal arteriole narrowing and vasospasm to reduce flow.
In the sclerotic phase, the layers of the endothelial wall undergo changes such as intimal thickening, medial hyperplasia, and hyaline degradation.
In the exudative phase, there is a disruption of the blood-retinal barrier, leading to retinal edema and hard exudates.