Hypertensive Retinopathy

Hypertensive retinopathy (HR) is a possible complication of high blood pressure (hypertension). Persistent, untreated high blood pressure can cause damage to the retina, the tissues at the back of the eye responsible for receiving the images we need to see.

The condition can lead to symptoms including double or dim vision, loss of vision and headaches. Treating hypertensive retinopathy typically involves controlling high blood pressure through lifestyle changes, medication and careful monitoring. Through this, the condition can be halted, and the damage may slowly heal.

Hypertensive retinopathy is an eyesight disorder that occurs as a result of high blood pressure. High blood pressure, also called hypertension, occurs when the force of blood against the artery walls is too high, causing the arteries to stretch, narrow and become damaged over time.

Hypertensive retinopathy occurs when the blood vessels supplying blood to the retina in the back of the eye become damaged. The likelihood of damage to the retina increases with the severity of high blood pressure and the length of time over which the condition is experienced.

Older people are most at risk of developing high blood pressure and are therefore also most at risk of developing hypertensive retinopathy.

Other factors that may contribute to the likelihood of developing high blood pressure include: 1

• Being overweight
• A sedentary lifestyle
• A diet high in salt
• Stress
• A family history of high blood pressure
• Diabetes
• Moderate to high alcohol intake

Most people will only develop symptoms of hypertensive retinopathy after there has already been significant damage to the retina. Before this, it may take a doctor or ophthalmologist (specialist eye doctor) to identify the condition.

Symptoms may include:

• Double or cloudy vision
• Headaches
• Loss of vision, when the condition has progressed significantly

If these symptoms come on very quickly, this can be a sign of severely high blood pressure and should be considered a medical emergency. Call a doctor immediately.

Ophthalmologists grade hypertensive retinopathy using four categories or stages. The classification system is known as the Keith Wagener Barker (KWB) grades. 1

• Grade 1: High blood pressure and narrowing of the arteries is mild. Generally, no symptoms are present.
• Grade 2: High blood pressure and narrowing of the arteries is more pronounced. Generally no symptoms are present.
• Grade 3: Signs of damage such as retinal haemorrhage (bleeding) and cotton wool spots, i.e. white patches on the retina, are present upon inspection. Symptoms may be present.
• Grade 4: Severe Grade 3 plus swelling of the optic disc (papilledema). Symptoms are present.

Some medical professionals may prefer to use the Mitchell-Wong grading system; a simplified version of the Keith Wagener Barker grades. This system simply combines the first two categories into one.

Diagnosing hypertensive retinopathy typically involves an examination by an ophthalmologist based on the symptoms present.

In some cases, an ophthalmoscope may be used to investigate the retina in the back of the eye. This instrument shines light into the eye, allowing doctors to see any signs of damage.

More rarely, a test known as a fluorescein angiography may be performed to investigate the blood flow into the retina. This involves taking pictures of the eye before and after a special fluorescein dye has been injected into the system and passed through the blood vessels of the eye. 1

The only way to treat hypertensive retinopathy is by controlling high blood pressure. This can be done through lifestyle changes such as:

• Giving up smoking
• Losing weight
• Taking regular exercise
• Dietary changes
• Reducing alcohol intake

Medication, such as ACE inhibitors, angiotensin-2 receptor blockers (ARBs), thiazide diuretics, calcium channel-blockers and beta-blockers may also be prescribed to help lower blood pressure levels. These medications can help to allow the retina to heal and stop further damage from occurring.

The type of medication chosen will depend on the affected person’s medical history and a consideration of the possible side-effects.

Preventing hypertensive retinopathy is possible through careful management of high blood pressure and related conditions, such as diabetes. Lifestyle changes, such as losing weight or giving up smoking, may be useful in achieving this. People with high blood pressure should also have their blood pressure regularly tested and be screened for eye problems.

Individuals with hypertensive retinopathy are at risk of various complications, including:

• Retinal vein occlusion occurs when a vein in the retina becomes blocked due to clots.
• Retinal artery occlusion occurs when an artery in the retina becomes blocked due to clots, resulting in possible loss of vision.
• Ischemic optic neuropathy involves the normal blood flow to the eye being blocked, resulting in damage to the optic nerve, the part of the eye which transmits images to the brain.
• Malignant hypertension causes blood pressure to increase rapidly, causing possible loss of vision. This is a rare complication, which is potentially life-threatening.

Hypertensive retinopathy is also linked to an increased risk of stroke and heart attack.

The outlook for people with mild (grade 1 or 2) hypertensive retinopathy is relatively positive, so long as blood pressure levels are controlled. If, however, severe hypertensive retinopathy is not properly managed, the condition can enter a “malignant” stage, which is associated with a relatively poor prognosis. 2

• Fundus hypertonicus

Q: Can hypertensive retinopathy be reversed?
A: It depends on the extent of damage to the retina. In many cases, the damage caused by hypertensive retinopathy can slowly heal if the necessary steps to lower one’s blood pressure are taken. These steps may include making lifestyle changes such as giving up smoking and losing weight, as well as taking medication as prescribed by a doctor.

Q: What is the difference between hypertensive retinopathy and diabetic retinopathy?
A: Hypertensive retinopathy is caused by high blood pressure. While having high blood pressure can increase the risk of diabetic retinopathy, this condition is a complication of diabetes, meaning anyone with diabetes type 1 or type 2 can potentially develop the condition. Like hypertensive retinopathy, diabetic retinopathy causes damage to the retina at the back of the eye and can, if left untreated, lead to blindness. 3

Q: Can high blood pressure cause double vision?
A: Yes, double vision can, in some cases, be a symptom of high blood pressure, specifically when high blood pressure has led to hypertensive retinopathy. If this symptom occurs very suddenly, a doctor should be contacted urgently.