High blood pressure and eye disease
Hypertensive retinopathy
High blood pressure can damage blood vessels in the retina. The retina is the layer of tissue at the back part of the eye. It changes light and images that enter the eye into nerve signals that are sent to the brain.
Damage to the retina from high blood pressure is called hypertensive retinopathy. It occurs as the existing high blood pressure causes changes to the microvasculature of the retina. Some of the first findings in the disease are flame hemorrhages and cotton wool spots. As hypertensive retinopathy progresses, hard exudates can appear around the macula along with swelling of the macula and the optic nerve, causing impairment of vision. In severe cases permanent damage to the optic nerve or macula can occur.
The retina is the internal layer of the eye that receives and transmits focused images. The retina is normally red due to its rich blood supply.
Causes
The higher the blood pressure and the longer it has been high, the more severe the damage is likely to be.
You have a higher risk of damage and vision loss when you also have diabetes, high cholesterol level, or you smoke.
Rarely, very high blood pressure develops suddenly. However, when it does, it can cause severe changes in the eye.
Other problems with the retina are also more likely, such as:
- Damage to the nerves in the eye due to poor blood flow
- Blockage of the arteries that supply blood to the retina
- Blockage of the veins that carry blood away from the retina
Carrying a lot of extra weight around your middle or sprinkling too much salt onto your food at each meal can cause high blood pressure, otherwise known as hypertension. Stress and your genes can also bring your blood pressure up. Sometimes when your blood pressure is high, your doctor might not be able to find any direct cause for it. That's what's called essential hypertension. When your doctor talks to you about your blood pressure, he's referring to the force of your blood pushing against your artery walls. The top number in your blood pressure is called the systolic blood pressure. That's the pressure in your blood vessels while your heart is pumping. The bottom number is called the diastolic blood pressure and that's the pressure when your heart rests between beats. You want your blood pressure to stay at 120 over 80 or less. A blood pressure of 140 over 90 or more is considered high. Why is high blood pressure a problem, you ask? Well, you can think of high blood pressure as being like a river that's rushing too hard, eventually it's going to damage its banks. With high blood pressure, the extra force of your blood pushing against your artery walls eventually damages them. It can also damage your heart, your kidneys, and other organs. So, how do you know if you have high blood pressure? Often you don't know, because high blood pressure doesn't have symptoms like a fever or cough. Usually there are no symptoms at all, and you won't be able to find out that you have high blood pressure unless you've had it checked, or you've developed complications like heart disease or kidney problems. You can check your blood pressure yourself with a home monitor, or have it checked at your doctor's office. If it's high, you and your doctor will set a blood pressure goal. You can achieve that goal in different ways, like eating a healthy diet, exercising for at least 30 minutes a day, quitting smoking, eating less than 1,500 milligrams of salt per day, and using programs like meditation and yoga to relieve your stress. But if these lifestyle changes aren't enough, your health care provider might prescribe one or more medicines to lower your blood pressure. The reason why doctors are so serious about a patients' blood pressure is that having uncontrolled blood pressure can cause a lot of serious health problems, including heart attack, stroke, kidney disease, and loss of vision. When it comes to your blood pressure, it's best to be proactive. Call your doctor for a check-up if you haven't had one in a while, and get your blood pressure checked. If it's high, follow your doctor's advice for bringing it back into a healthy range.
Symptoms
Most people with hypertensive retinopathy do not have symptoms until late in the disease.
Symptoms may include:
- Double vision, dim vision, or vision loss
- Headaches
Sudden symptoms are a medical emergency. It often means that the blood pressure is very high.
Exams and Tests
Your health care provider will use an ophthalmoscope to look for narrowing of the blood vessels and signs that fluid has leaked from blood vessels.
The degree of damage to the retina (retinopathy) is graded on a scale of 1 to 4:
- Grade 1: Usually you would not have symptoms.
- Grades 2 to 3: There are a number of changes in the blood vessels, leaking from blood vessels, and swelling in other parts of the retina.
- Grade 4: You will have swelling of the optic nerve and of the visual center of the retina (macula). This swelling can cause decreased vision.
You may need a special test to examine the blood vessels.
Treatment
The only treatment for hypertensive retinopathy is to control high blood pressure.
Outlook (Prognosis)
People with grade 4 (severe retinopathy) often have heart and kidney problems due to high blood pressure. They are also at higher risk for stroke.
In most cases, the retina will heal if the blood pressure is controlled. However, some people with grade 4 retinopathy will have lasting damage to the optic nerve or macula.
When to Contact a Medical Professional
Get emergency treatment if you have high blood pressure with vision changes or headaches.
References
Cheung CY, Wong TY. Hypertension. In: Sadda SVR, Sarraf D, Freund KB, et al, eds. Ryan's Retina. 7th ed. Philadelphia, PA: Elsevier; 2023:chap 52.
Levy PD, Brody A. Hypertension. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 70.
Rachitskaya AV. Hypertensive retinopathy. In: Yanoff M, Duker JS, eds. Ophthalmology. 5th ed. Philadelphia, PA: Elsevier; 2019:chap 6.18.
Version Info
Last reviewed on: 8/22/2022
Reviewed by: Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
