Hypertensive Retinopathy

What is Hypertensive Retinopathy?

Hypertensive retinopathy is a condition that causes unusual changes of the retina due to high blood pressure. The retina is a tissue found at the back of your eye and it converts light into nerve signal so that the brain can easily interpret it ³.

Normally, the retinal arteries are able to control their own shape according to changes in systemic blood pressure. However when this pressure exceeds 140/110 mmHg, they are unable to control it. This can seriously affect your retina.

Hypertensive retinopathy can affect persons of any age who have had uncontrolled high blood pressure. Male and female are equally affected. Some studies reveal that this condition is more prevalent in African countries because of high incidences of high blood pressure in these countries¹.

Causes

High blood pressure

Hypertensive retinopathy occurs due to increased blood pressure in the retinal arteries. The high blood pressure damages blood vessels in the retina in different ways. The following are some of the ways high blood pressure affects retinal blood vessels:⁴

• High blood pressure causes blood vessels to become narrow and makes arteries and veins to cross over each other.
• When blood vessels change shape, they leak blood easily which contain fats and other fluids. This leaking can cause the optic nerve and macula to swell.
• When retina is detached, other nearby areas can become swollen.

Risk factors

Several factors and conditions can elevate your risk for hypertensive retinopathy. They include:¹

• People with prolonged high blood pressure or chronic hypertension are at a risk of developing this condition. When your systemic blood pressure of 140/110mmHg, you are a candidate for advanced hypertensive retinopathy. When your systemic pressure is 180/120mmHg, you have reached a malignant stage of this condition. This pressure causes optic nerve to swell and you can bleed in the retina.
• Those people who have heart attack can develop this condition.
• Diabetic people are also at risk
• Those who are overweight experience high blood pressure which causes hypertensive retinopathy.
• Having high cholesterol level elevates your blood pressure which can cause this condition.
• Those who smoke are at risk of developing this condition.
• Drinking excess alcohol makes you vulnerable to hypertensive retinopathy.
• Those people with atherosclerosis, a condition where blood vessels become hard and narrow. This increases blood pressure and can cause hypertensive retinopathy.

Symptoms

The main symptom of this condition is changed vision which can be accompanied by headache. This is characterized by the following:⁴

• Blood vessels become twisted and veins and arteries cross each other.
• Bleeding occurs in the retina
• Regions in the retina become yellow because of lack of oxygen.
• The macula becomes swollen due to leakage of blood which has fat. This can cause loss of vision.
• Other area of the retina become swollen and can make the retina to get detached from its place, a condition known as Retinal edema.
• The optic nerves become swollen, a condition known as Papilledema. When you experience Papilledema, seek urgent medical attention.

Complications

Hypertensive retinopathy can cause undesirable and serious complications. These complications include:²

Optic nerve atrophy

As the optic nerves swell, they become damaged leading to optic nerve atrophy. This condition can be as a result of many causes including hypertensive retinopathy.

Retinal detachment

When the retina swells, it may get detached from its usual place.

Ischemia

When retina arteries become narrow or are obstructed, oxygen supply to the retina is cut off causing Ischemia.

Vitreous hemorrhaging

Vitreous hemorrhaging and Retinal arterial macroaneurysms : hypertensive retinopathy can cause painful bleeding in spaces of the retina.

Occlusion

This is where blood vessels of the retina are blocked. This prevents oxygen from reaching the retina.

Diagnosis

Hypertensive retinopathy can be diagnosed through the following methods:

Ophthalmoscope

Your doctor will examine your retina using a tool known as ophthalmoscope. The doctor uses this tool which shines light via the pupil to assess the backside of your eye for any leakage of fluid from the blood vessels and narrowing of these vessels. This will take about 10 minutes and it is painless.

Fluorescein Angiography

Your doctor can also use fluorescein angiography to examine your retina. In this test, your doctor applies a particular dye on the pupil to enlarge it and take pictures of the inside of your eye. After this is done, your doctor injects a dye called fluorescein into a vein located in your elbow and takes more pictures as the dye flows through the blood vessels.

Classification

The severity and extend of hypertensive retinopathy is represented on a scale of 1 to 4. This scale is called Keith–Wagener–Barker Classification System. These four grades include:³

• Grade 1: The retinal artery is narrowed but this not so serious.
• Grade 2: It is similar to grade 1; however the narrowing of the retina artery is severe in grade 2.
• Grade 3: Symptoms of grade 2 are present in grade 3. Other additional symptoms include bleeding in the retina, retina edema, etc.
• Grade 4: This grade has painful symptoms of grade 3 and it is characterized by swellings in the optic nerve (papilledema). Patients with grade 4 retinopathy are at higher risk for heart disease, kidney problem and stroke.

Treatment

Hypertensive retinopathy can be effectively managed through a combination of various medication and lifestyle changes that lowers high blood pressure.

Medications

Your doctor may recommend medications that lower high blood pressure such as beta blockers, diuretics, etc.

Life style changes

You can adjust your lifestyle to help you lower the risk of Hypertensive retinopathy. You can do this by eating a healthy diet which is rich in vegetable and fruits to reduce high blood pressure. Exercise regularly, take little salt, and limit the amount of alcohol or coffee. Stop smoking if you smoke and try to lose weight if you are overweight.

Reference List

1. Hypertensive retinopathy – http://www.healthline.com/health/hypertensive-retinopathy#outlook9
2. http://www.dovemed.com/diseases-conditions/hypertensive-retinopathy/
3. https://medlineplus.gov/ency/article/000999.htm
4. Hypertensive retinopathy http://www.merckmanuals.com/en-ca/professional/eye-disorders/retinal-disorders/hypertensive-retinopathy
5. Ischemia http://www.webmd.com/a-to-z-guides/tc/ischemia-topic-overview