Hypertensive Retinopathy

What is Hypertensive Retinopathy?

When high blood pressure isn’t properly controlled, it can negatively affect several parts of your body, including your blood vessels, kidneys, brain, and eyes. This can cause damage to vital organs, which medical professionals refer to as “target-organ damage”.

High blood pressure can hurt three different parts of the eye: the choroid (the layer of blood vessels and connective tissue between the white of the eye and retina), the retina (the layer at the back of the eye that detects light and color), and the optic nerve (the nerve that sends signals from your eye to your brain).

Hypertensive retinopathy is the term used when high blood pressure harms the blood vessels in the retina. There is strong evidence to suggest that hypertensive retinopathy may indicate the risk of severe health issues and heighten chances of death because of organ damage caused by high blood pressure. According to a study by Erden et al., the more severe and prolonged the high blood pressure, the more likely it is that retinopathy will occur.

What Causes Hypertensive Retinopathy?

There are various factors that contribute to the development of hypertensive retinopathy, besides essential and secondary hypertension. Hypertensive retinopathy is a condition that damages the eye’s retina due to high blood pressure.

Interestingly, studies have found that Afro-Caribbean individuals and women tend to have hypertensive retinopathy more often than Europeans and men respectively. However, it isn’t just about your racial background or sex, your genes may also have a role to play. Certain genes are associated with a greater risk of developing this condition. One study found that a particular gene deletion is associated with a higher risk.

Another factor that plays a role is smoking. It’s been found to be strongly connected with severe forms of hypertensive retinopathy. Also, if your kidneys aren’t working well (characterized by persistent protein in the urine and low creatinine clearance, which is a test that evaluates kidney function), you may have a higher chance of developing hypertensive retinopathy.

Finally, a hormone from fat cells called leptin could be involved too. Research has shown that people with hypertensive retinopathy tend to have high levels of leptin in their blood. It is thought that leptin could cause damage to the lining of the blood vessels, which might be linked to hypertensive retinopathy. However, more research is needed to understand how these factors contribute to the risk and development of the disease.

Risk Factors and Frequency for Hypertensive Retinopathy

Research has found that the seriousness and length of high blood pressure, or hypertension, directly affects the likelihood of developing hypertensive retinopathy, a condition which affects the eye. Studies show a significant number of patients with hypertension develop this condition – in some studies, more than half of the patients. They’ve also found chronic kidney disease is a key factor in predicting severe hypertensive retinopathy. Research has identified different grades of this condition too, with 37% of hypertension patients having grade 1 hypertensive retinopathy, and 17% having grade 2.

• The risk of getting hypertensive retinopathy increases with the severity and duration of hypertension.
• One study found 66.3% of hypertension patients developed hypertensive retinopathy.
• Another study recorded an even higher incidence, reporting 83.6% of hypertension patients developed the condition.
• Chronic kidney disease was identified as a significant risk factor for severe hypertensive retinopathy.
• In terms of the severity of the effect on the eyes, 37% of hypertension patients had grade 1 hypertensive retinopathy.
• Meanwhile, 17% had grade 2 hypertensive retinopathy.

Signs and Symptoms of Hypertensive Retinopathy

Hypertensive retinopathy, a condition affecting the eye due to high blood pressure, often doesn’t show symptoms and is identified through an eye examination. Specific signs of this condition are identified in different areas of the eye:

• Changes at the points where arteries and veins cross:
  • Salus’s sign: The retinal vein displaces as it passes the artery.
  • Gunn’s sign: The retinal vein shrinks on the sides where it intersects with the arteriole.
  • Bonnet’s sign: The retinal vein abnormally bends after crossing the arteriole.
• Changes in the arteries:
  • Decreased arteriovenous ratio to 1:3 (the regular ratio is 2:3).
  • The artery’s light reflex changes, taking on a copper or silver appearance.
• Changes in the retina:
  • Bleedings:
    • Dot-blot hemorrhages: Blood seeping into the inner layer of the retina.
    • Flame-shaped hemorrhage: Bleeding happening in the superficial layer of the retina.
  • Exudates (fluid that has seeped out of blood vessels):
    • Hard exudates: Deposits of fat in the retina.
    • Soft exudates: These look like cotton wool spots on the retina due to inadequate blood supply to the nerve fibers.
• Changes in the macula (central part of the retina):
  • Star-shaped formation due to the accumulation of hard exudates around the macula.
• Changes in the optic nerve:
  • Swelling of the optic disk, also known as hypertensive optic neuropathy.

A study identified certain eye signs that indicated a higher risk for stroke. These include AV nicking, local narrowing of the arteriole (linked with hardening of the arteries), small balloon-like protrusions in the arteries (microaneurysms), cotton wool spots, retinal bleedings (dot blot and flame-shaped), and decreased AV ratio.

Testing for Hypertensive Retinopathy

When checking for hypertensive retinopathy, a condition caused by high blood pressure affecting the eyes, doctors use different classification systems. These systems help doctors pinpoint the specific features of the disease based on an examination of the back of the eye (called a fundus examination). This is done with a special tool called an indirect ophthalmoscope or a +90 D lens.

One of these classification systems is the Keith-Wagner-Barker classification:

• Group 1: Slight narrowing of small blood vessels in the retina (retinal arterioles)
• Group 2: Group 1, plus focal narrowing of retinal arterioles and changes in the point where arteries and veins cross (AV nicking)
• Group 3: Group 2, plus flame-shaped bleeding spots in the eye (haemorrhages), white patches resulting from damage to nerve fibers (cotton-wool spots), and deposits of fats or proteins (hard exudates)
• Group 4: Group 3, plus swelling of the optic disc (the area where the optic nerve enters the eyeball)

The Scheie Classification is another system used:

For Hypertensive Retinopathy:

• Stage 0: No visible abnormalities
• Stage 1: Diffuse narrowing of the arterioles (small artery branches)
• Stage 2: Stage 1 plus focal arteriolar constriction (further narrowing in certain parts)
• Stage 3: Stage 2 plus retinal hemorrhage (bleeding in the retina)
• Stage 4: Stage 3 plus hard exudates, retinal edema (swelling due to fluid), and optic disc swelling

For Arteriosclerosis (hardening or thickening of arteries) :

• Stage 0: Normal
• Stage 1: Broadening of arteriolar light reflex (increased light reflection from arterioles)
• Stage 2: Stage 1 plus AV crossing changes
• Stage 3: Copper wiring of arterioles (a sign that arterioles look like copper wire due to thickening)
• Stage 4: Silver wiring of arterioles (a severe sign where arterioles show a silvery appearance)

Treatment Options for Hypertensive Retinopathy

Screening for hypertensive retinopathy or damage to the retina due to high blood pressure is important. The retina’s blood vessels are directly visible during routine eye examinations, which allows doctors to easily see the effects of prolonged high blood pressure. This damage can indicate similar changes occurring in blood vessels of other organ systems in the body.

It is crucial therefore that eye doctors and general physicians collaborate. This will ensure that patients with high blood pressure are properly checked for signs of such damage, and receive timely treatment if necessary, reducing the risk of further health complications in the eyes and other systems of the body. Interestingly, a study has shown that hypertensive retinopathy is associated with an increased risk of stroke even after blood pressure and other stroke risk factors have been controlled.

The approach to treating hypertensive retinopathy depends on the severity of the disease:

– Mild hypertensive retinopathy: This can be managed by keeping blood pressure under control with regular monitoring.
– Moderate hypertensive retinopathy: This requires referral to a general physician. They’ll check for other co-existing conditions like diabetes and cardiovascular abnormalities. Controlling and monitoring blood pressure is a must.
– Severe hypertensive retinopathy: This requires urgent treatment and referral because it’s closely linked with an increased risk of death. Doctors will also need to check for signs of damage in other organs such as the kidneys, heart, and brain.

It’s important to note that lowering blood pressure should be done in a controlled way to prevent damage to critical organs like the optic nerve in the eye and the brain.

What else can Hypertensive Retinopathy be?

There are several conditions that can cause swelling in the optic disc, similar to certain eye diseases. These include:

• Diabetic papillopathy
• Central retinal vein occlusion
• Anterior ischemic optic neuropathy
• Neuroretinitis

Similarly, chronic hypertensive retinopathy can be confused with various other medical conditions, such as:

• Diabetic retinopathy
• Retinal venous obstruction
• Hyperviscosity syndrome
• Ocular ischemic syndrome
• Radiation retinopathy

What to expect with Hypertensive Retinopathy

Chronic hypertensive retinopathy, a condition affecting the retina due to high blood pressure, rarely leads to significant vision loss. Treating the high blood pressure can stop the progression of the changes to the retina. However, the narrowing of small arteries in the eye and abnormalities in the way arteries and veins cross each other often still continue.

If malignant hypertension (a dangerous form of high blood pressure) is left untreated, the risk of death is significantly high with up to 50% dying within 2 months of diagnosis and nearly 90% by the end of one year.

Vision loss in people suffering from hypertensive retinopathy can result from two conditions: secondary optic atrophy, a condition involving damage to the optic nerve due to prolonged swelling, or changes in the retina’s pigment layer following a fluid-filled separation of the retina.

Possible Complications When Diagnosed with Hypertensive Retinopathy

The complications of the condition can include:

• Blockages in the arteries or veins of the retina
• Large swelling of a small artery in the retina
• Diabetic retinopathy, a condition that damages the blood vessels of the retina. When this and high blood pressure-related retinopathy occur in a patient at the same time, it is known as mixed retinopathy. Also, high blood pressure is one of the significant risk factors that can make diabetic retinopathy worse.
• Anterior ischemic optic neuropathy, a condition that leads to damage in the optic nerve due to insufficient blood supply
• Age-related macular degeneration, a condition that blurs your central vision
• Glaucoma, a condition that damages the optic nerve and can result in vision loss
• Blockages in the small arteries of the retina
• Formation of a thin layer of fibrous tissue on the surface of the retina
• An eye condition known as cystoid macular edema resulting in retinal swelling