What is hypertensive retinopathy?
The retina is the tissue layer located in the inner surface of the back of your eyeballs. This tissue layer transforms light into nerve signals that are then sent to the brain for understanding.
When your blood pressure is too high, it can cause damage to your retina's blood vessels, restricting the retina’s function, and put pressure on the optic nerve, causing loss of vision. This condition is called as Hypertensive Retinopathy (HR).
Pathophysiology: Hypertensive crisis may cause optic disk edema and Severe blood pressure elevation to cause reversible vasoconstriction in retinal blood vessels, exudative vascular changes occur when patient with more prolonged or severe hypertension, this also leads necrosis and consequence of endothelial damage. Other changes like arteriovenous nicking, arteriole wall thickening typically need years of elevated blood pressure to improve. Smoking is an important risk factor for increasing hypertensive retinopathy.
Generally, hypertension combined with diabetes increases the risk of vision loss, and also hypertension is a major risk factor for other retinal disorders like diabetic retinopathy, vein occlusion or retinal artery.
Symptoms of Hypertensive Retinopathy No symptoms are noticed until the disease has progressed extensively. The possible signs and symptoms include reduced vision, eye swelling, bursting of blood vessels and headaches.
Prolonged, poorly controlled hypertension may cause the following can develop:
Permanent arterial narrowing
Arteriosclerosis severe vascular wall hyperplasia and thickening and moderate vascular wall changes
If the disease is severe, the following can develop:
Cotton-wool spots (abnormal finding on the fundoscopic exam of the retina of the eye)
Yellow hard exudates
Optic disk edema
Get medical help immediately if your blood pressure is high and you suddenly have changes in your vision.
What Causes Hypertensive Retinopathy? Hypertension Retinopathy mainly occurs by prolonged high blood pressure, or hypertension. High BP is a chronic problem in which the force of the blood against your arteries is too high.
The force is a result of the blood pumping out of the heart and into the arteries also the force generated as the heartbeats between heart rests.
When the blood flows through the body at a higher pressure, the tissue that makes up the arteries will start to stretch and finally to become damaged.
Hypertension Retinopathy commonly occurs after your blood pressure has been consistently high over a prolonged period. Your blood pressure levels can be affected by:
A lack of physical activity
Having too much salt
A stressful lifestyle
Stages and classification of Hypertensive Retinopathy The stages or classification of Hypertensive Retinopathy can be represented from grade 1 to 4
Grade 1(Vasoconstrictive Phase) : Mild retinal arteriolar narrowing.
In this grade type, local autoregulatory mechanisms play a major role. This causes retinal arteriolar narrowing and vasospasm which is evident by the decrease in the arteriole to venule ratio (Normal = 2:3).
Grade 2 (Sclerotic Phase) : Severe arteriovenous nipping and focal narrowing.
Persistent increases in blood pressure cause some certain changes in vessel wall. Which may lead to
Media layer: Hyperplasia
Intima layer: Thickening
Arteriolar wall: Hyaline degeneration
This leads to arteriolar narrowing, arteriovenous (AV) crossing changes, and widening and accentuation of light reflex (silver and copper wiring). arteriovenous crossing changes occur when a thickened arteriole crosses over a venule and subsequently compresses it as the vessels share a common adventitious sheath. The vein, in turn, appears dilated and tortuous distal to the arteriovenous crossing.
Grade 3 (Exudative Phase): includes Grade 2 signs and also exudates, cotton wool spots (retinal ischemia), and retinal hemorrhages (flame-shaped and dot blot).
This case is noticed in the patient with increased BP, characterized by leakage of blood and plasma vessel was obstructing the autoregulatory mechanism and blood brain barriers.
Grade 4(Malignant Hypertension): Severe grade 3 retinopathy symptoms plus papilledema.
Severe intracranial hypertension leads to optic nerve ischemia and edema (papilledema).
Fibrinoid necrosis of choroidal arterioles occurs leading to segmental infarction of choriocapillaris. This gives rise to:
Elschnig's spots: Where the overlying retinal pigment epithelium (RPE) appears yellow
Siegrist's streak: RPE hyperplasia over choroidal infarcts
Neurosensory RPE detachments
Grade 1 doesn't show any detectable symptoms. However, at Grade 4 the optic nerve swells cause severe loss of vision problems
Treatment for Hypertensive Retinopathy
Reducing blood pressure is the main treatment of hypertensive retinopathy
The severe hypertensive retinopathy treatment involves decreasing systemic blood pressure below 140/90 mmHg. Hypertension can be achieved by any of the armamentarium of medical treatments. Medical treatment can only treat severe changes in hypertension from vascular leakage and vasospasm. There is no treatment identified for arteriosclerotic changes in increased hypertension.
Drugs are commonly used for the outpatient to decrease blood pressure include calcium channel blockers, diuretics, and angiotensin-converting enzyme inhibitors. α-adrenergic blockers, central α2-adrenergic agonists and direct vasodilators are less commonly used medications
Medical follow up
Medical follow up dependent upon the degree of hypertension and resistance to medications.
There is no surgical treatment required for ocular complications/hypertension. In cases of secondary hypertension surgical treatment may be useful, based on the etiology.