Hypertensive Retinopathy

By Eyecare NG

Overview   |  How it Develops   |   Symptoms   |   Risk Factors   |   Diagnosis   |   Management   |   Recommended Lifestyle Changes   |   Complications

Overview

Hypertensive retinopathy refers to the damage done to the retina and retinal blood vessels by prolonged systemic hypertension (high blood pressure). It is usually a late complication of hypertension.

There are rarely symptoms at the early stage of the disease. Hence, many people who have hypertension are usually not aware they have developed retinopathy until they undergo an eye examination.

Hypertensive retinopathy is mostly seen in middle-aged and elderly people and it is most common among Africans.

How it develops

When blood pressure remains high for prolonged periods, it causes the walls of the retinal blood vessels to thicken. This narrows the opening of the blood vessels. The narrowing of the blood vessels is usually worse if there are cholesterol deposits on the inner walls of the blood vessels. This condition decreases the amount of the blood that flows through the blood vessels and consequently reduces the amount of oxygen that gets to the retina. Due to the inadequate supply of oxygenated blood to the retina, patches of it get damaged. The damaged areas of the retina are seen as fluffy white lesions (known as cotton wool spots) during an eye examination.

As the retinopathy progresses, the following may occur; leaking of blood from retinal blood vessels, accumulation of fluids, swelling of the optic disc (papilledema), deposit of exudates around the macula and loss of vision.

Symptoms 

There are usually no symptoms at the early stages of hypertensive retinopathy.  If blood pressure remains poorly controlled, the condition progresses extensively and the following symptoms may be observed:

  • Decreased vision
  • Eye pain
  • Double vision
  • Headaches
  • Swelling of the eye

Risk factors

Risk factors for the development of hypertensive retinopathy include:

  • Prolonged high blood pressure
  • Being overweight or obese
  • Heart disease
  • Diabetes
  • Smoking
  • Arteriosclerosis (narrowing and thickening of blood vessels)
  • High cholesterol
  • Heavy alcohol consumption
  • Being of African descent
  • Women are more at risk than men
  • Eating an unhealthy diet

Diagnosis 

Diagnosis of hypertensive retinopathy is done following a comprehensive eye examination. Usually, the doctor will dilate the eye to ensure that a proper view of the retina is obtained. The retina and retinal blood vessels are directly observed for signs indicative of hypertensive retinopathy.

The presence of the following indicates that an individual has hypertensive retinopathy:

  • Cotton wool spots
  • Flame-shaped haemorrhages
  • A ring of exudates from the optic disc to the macula (known as macular star)
  • Optic nerve head swelling or oedema (papilledema)
  • Arteriosclerosis (characterized by thickened and hardened blood vessels with narrow openings)
  • Retinal and macular swelling or oedema (very rare)

To identify areas of blockages and leakages in the retina, a test known as Fluorescein angiography is done. To perform the test, fluorescein dye is injected into the bloodstream and photographs of the retinal background are taken.

During diagnosis, hypertensive retinopathy is graded based on the signs observed during an eye examination. The grades are as follows:

  • Grade 1: Mild narrowing of the retinal artery
  • Grade 2: Signs of grade 1 and a more severe/ tighter constriction of the retinal artery called arteriovenous (AV) nipping.
  • Grade 3: Signs of grade 2 with retinal swelling (oedema), fluffy white lesions on the retina (cotton wool spots) and retinal haemorrhage
  • Grade 4: Signs of grade 3 along with optic disc swelling (papilledema) and macular oedema.

Management 

Management of hypertensive retinopathy is targeted at controlling blood pressure by ensuring that it is kept below 140/90mmHg. Common management options are

  • Lifestyle changes
  • Use of medications to control blood pressure

People who are observed to have optic disc swelling (papilledema) at an eye care centre are usually referred immediately to the emergency unit of a hospital. This is because optic disc swelling is indicative of a potential medical crisis caused by extremely high blood pressure or other conditions such as brain tumour, bleeding in the brain, head injury or brain inflammation

When blood pressure is lowered to the normal range, cotton wool spots, deposits around the macula (macular star) and optic disc swelling (papilledema) resolve after some time. However, arteriosclerosis (thickening and narrowing of the blood vessels) are irreversible.

Recommended lifestyle changes

The following lifestyle changes are recommended for the prevention and management of hypertension and hypertensive retinopathy:

  • Eat a balanced diet
  • Control food portion sizes
  • Reduce salt intake
  • Perform regular physical activity and exercise
  • Reduce the amount of caffeine and alcoholic beverages consumed.
  • Quit smoking
  • Maintain a healthy weight.
  • Take your blood pressure medications regularly.
  • Get regular medical examination to ensure your blood pressure is well under control.
  • Get adequate rest and sleep

 Complications

  • Ischemic optic neuropathy: This is a permanent damage to the optic nerve (optic nerve death) caused by lack of or inadequate supply of blood and oxygen to the optic nerve. It results in a sudden loss of vision in one or both eyes.
  • Retinal artery occlusion: This is also known as ocular or eye stroke. It is a condition in which the retinal artery gets blocked (occluded), thereby cutting off blood supply to the retina. Vision loss occurs because the retina does not get enough blood and oxygen. The extent of vision loss is often dependent on the retinal artery and area affected.
  • Retinal vein occlusion: A condition in which the vein that takes blood away from the retina gets blocked. It causes a partial loss of vision.