Hypertensive retinopathy

Hypertensive retinopathy is an eye condition caused by high blood pressure. Over time, high blood pressure can damage the blood vessels in the eyes and affect eyesight. Early signs of hypertensive retinopathy include blurred vision and headaches. More severe symptoms, like sudden vision loss and bleeding into the eye, are also possible.

The information here can help you recognise symptoms of hypertensive retinopathy or find out more about the condition if you have already received a diagnosis.

Hypertensive retinopathy stages

Hypertensive retinopathy occurs in four stages:

• Stage 1 - Arteriolar narrowing: the blood vessels in the eye (retinal arterioles) tighten up and become narrower.
• Stage 2 - Arteriovenous nicking: pressure from the tiny arteries in the eyes squashes the veins next to them, causing them to bend out of shape.
• Silver wiring: some arterioles become blocked making them look whiter.
• Copper wiring: Some arterioles become thicker making them look more orange.
• Stage 3 - Exudation and cotton wool spots: pressure causes blood and hard exudates made of proteins and lipids to leak through the arteriolar wall and into the retina. The result is swelling, nerve fibre damage, and visual disturbances. Areas of the retina that have lost their blood supply look fluffy and white and are known as cotton wool spots.
• Stage 4 - Optic nerve oedema: extremely high blood pressure can push fluid into the tissues around the optic nerve (papilloedema), causing optic nerve atrophy or ischaemia (Sources: Science Direct, National Library of Medicine).

Hypertensive retinopathy grading

The four stages of hypertensive retinopathy come from the 1939 Keith-Wagener-Barker (KWB) grading system, later simplified by Wong, TY and Mitchell (Sources: StatPearls, New England J Med).

The grading system details the pathophysiology of hypertensive retinopathy. It helps clinicians differentiate it from other similar eye diseases, like diabetic retinopathy, retinal artery occlusion and retinal vein occlusion.

High blood pressure eye symptoms

The World Health Organization defines high blood pressure (hypertension) as 140/90mmHg.

Hypertension affects multiple body systems, including the brain, heart, vascular system, renal system and retina. This impact is known as target organ damage (Source: National Library of Medicine). An acute rise in blood pressure that requires urgent treatment is known as malignant hypertension or hypertensive crisis.

High blood pressure (BP) can go unnoticed for some time. The eyes are the only place in the body we can visualise blood vessels, and they can show end-organ damage that could suggest more widespread cardiovascular and heart disease. There are known links between hypertensive retinopathy and vascular changes, like atherosclerosis (Source: National Library of Medicine) and coronary heart disease (Source: Br J Ophthalmol).

Sometimes, ocular abnormalities can be the first sign of high blood pressure. You may need antihypertensive treatment to bring down your blood pressure if this happens.

High blood pressure can damage the optic nerve, ocular tissue and blood vessels, and accelerate diabetic retinopathy. Elevated BP also has implications for glaucoma development and age-related macular degeneration (Source: Lancet). If fluid from the choroidal blood vessels leaks and builds up underneath the retina, it can cause vision changes.

Eye-related signs and symptoms to look out for include bloodshot eyes, eye floaters, wavy vision and sudden, painless vision loss.

Can high blood pressure cause blurred vision?

Blurred vision could be a sign of hypertensive retinopathy. High blood pressure can push fluid out of the blood vessels and into the eye’s tissues, building up around the optic nerve and retina. This leakage can impact vision, causing blurred vision and other eyesight changes, like wavy or double vision.

Blurred vision can be a sign of pre-eclampsia for pregnant women, a serious condition characterised by high blood pressure that needs urgent medical attention.

High blood pressure and vision disturbance

Any change to your vision could be an indication of hypertensive retinopathy. Increased pressure in the eyes can damage the blood vessels and surrounding tissues over time, leading to various vision changes, including blurring, eye floaters and seeing double.

If you experience any symptoms of hypertensive retinopathy, your doctor may decide to carry out an eye exam called a fundoscopy.

What is hypertensive retinopathy fundoscopy?

A fundoscopy is an eye examination where an ophthalmologist or doctor uses an ophthalmoscope or slit-lamp microscope to visualise the back of the eye. The retina, optic nerve and blood vessels (and the macula if medication is used to dilate the pupil) become visible (Source: Clinical Methods).

Fundus photography can help diagnose hypertensive retinopathy or other medical conditions that affect the vascular system, like diabetes and endocarditis (Source: Stanford Medicine). Your doctor may also use other diagnostic ophthalmology tests called fundus fluorescein angiography and optical coherence tomography angiography (Source: Scientific Reports).

What does hypertensive retinopathy look like?

During a fundoscopy, the doctor is looking for specific signs that might indicate hypertensive retinopathy, such as:

• Changes to the places where the tiny arteries and veins cross (arteriovenous crossing)
• A copper or silver wiring appearance
• Retinal haemorrhages
• Soft or hard exudates
• Optic disc swelling
• Hard exudate deposits around the macula

Hypertensive retinopathy treatment