What is hypertensive retinopathy
Hypertensive retinopathy (HR) is a complication of high blood pressure (hypertension). Persistent, untreated high blood pressure can cause damage to the retina, tissues at the back of the eye, responsible for receiving the images we need to see, resulting in 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.
Causes of hypertensive retinopathy
Hypertensive retinopathy is an eyesight disorder that occurs as a result of high blood pressure. High blood pressure 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 contribute to the likelihood of developing high blood pressure include:
- Being overweight
- A sedentary lifestyle
- A diet high in salt
- A family history of high blood pressure
- Moderate to high alcohol intake
Symptoms of hypertensive retinopathy
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 (eye doctor) to identify the condition.
Symptoms may include:
- Double or cloudy vision
- 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.
Hypertensive retinopathy grading
Ophthalmologists grade hypertensive retinopathy using four categories. The classification system is known as the Keith Wagener Barker (KWB) grades.
- 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.
Hypertensive retinopathy diagnosis
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.
Hypertensive retinopathy treatment
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 will 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.
Hypertensive retinopathy prevention
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.
Hypertensive retinopathy complications
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.
Other names for hypertensive retinopathy
- Fundus hypertonicus