Alternative Names changes in the retina due to high blood pressure
What is going on in the body? High blood pressure occurs in about 5% of the population. Half of these people do not know that they have the condition. Eighty-five to 90% of cases of high blood pressure have no known cause. This is called essential hypertension. Essential hypertension affects women more than men and is more common among blacks. It tends to run in families.
Hypertensive disease refers to problems in the blood vessels in the kidneys, brain, heart, and eyes that are brought on by high blood pressure. Hypertensive retinopathy (ret-in-ah-path-ee) is a disease of the retina, the light-sensing layer of nerves at the back of the eyeball. These problems may appear 10 to 15 years after high blood pressure is first diagnosed.
There are no actual arteries in the eye but rather small blood vessels called arterioles. When blood pressure is poorly controlled, these vessels undergo a number of changes. The vessels narrow and become constricted in places. True hypertensive retinopathy occurs in cases of very high blood pressure that has gone untreated for a long time. Vision worsens as more and more of the retina is affected by these changes. Sharpness of vision decreases significantly when the central retina, or macula, suffers changes.
What are the signs and symptoms of the disease? High blood pressure often has no symptoms. In severe cases, it may cause blurred vision. This may come on suddenly or gradually. High blood pressure can lead to hardening or thickening of the small arteries that supply the retina. The changes in the blood supply can affect the way the eye functions. This can lead to blurry vision. The blurring is due to the leaking of tiny amounts of fluid from the blood vessels in the retina. In very severe cases, vision can be partially or totally lost. There is usually no pain and very little redness of the eye associated with this condition.
What are the causes and risks of the disease? Most cases of high blood pressure have no known cause. Some people, however, have risk factors that make them more prone to the disease. When not properly treated, high blood pressure causes damage to the small blood vessels in eyes as well as to the kidney, heart, and brain.
What can be done to prevent the disease? Keeping blood pressure within a normal range can prevent damage to the retina. This will prevent broken blood vessels and swelling of the retina, which leads to vision loss.
How is the disease diagnosed? Hypertensive retinopathy is diagnosed by viewing the blood vessels in the retina through the dilated pupil. A lighted microscope, called an ophthalmoscope is used for this purpose. Using this device, a doctor may find:
narrowed blood vessels with an abnormal colour
bleeding in both the surface and the deep layers of the retina
feathery white areas called exudates
fluid collecting in the blood vessels, causing them to bulge
The damage to the retina is graded on a scale of I to IV. At grade I, there are no symptoms and at grade IV there problems with vision and swelling of the optic nerve, the nerve that connects the eye to the brain.
What are the long-term effects of the disease? Poorly managed high blood pressure can lead to severe vision problems. In addition it can cause damage to the kidneys, heart, and brain. This damage may take the form of stroke, kidney failure, or heart failure.
What are the treatments for the disease? Treatment for hypertensive retinopathy consists of keeping high blood pressure under control. This includes eating a proper diet, exercising, and practicing relaxation techniques. Medications such as diuretics ("water pills" that increase urine production), such as frusemide or hydrochlorothiazide, and blood pressure lowering drugs, such as propranolol, lisinopril, or verapamil, are frequently needed as well.
What are the side effects of the treatments? The side effects depend on the medications used to treat high blood pressure.
How is the disease monitored? Monitoring high blood pressure means checking blood pressure regularly. It also includes medical examinations of the heart, kidneys, and eyes to make sure that complications are not developing.
Author: William Stevens, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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