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.
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 develop suddenly. However, when it does, it can cause severe changes in the eye.
Other problems with the retina are also more likely, such as:
Most people with hypertensive retinopathy do not have symptoms until late in the disease.
Symptoms may include:
- Double vision, dim vision, or vision loss
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: You may 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.
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.
Levy PD, Brody A. Hypertension. In: Walls RM, Hockberger RS, Gausche-Hill M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 74.
Rachitskaya AV. Hypertensive retinopathy. In: Yanoff M, Duker JS, eds. Ophthalmology. 5th ed. Philadelphia, PA: Elsevier; 2019:chap 6.18.
Yim-lui Cheung C, Wong TY. Hypertension. In: Schachat AP, Sadda SVR, Hinton DR, Wilkinson CP, Wiedemann P, eds. Ryan's Retina. 6th ed. Philadelphia, PA: Elsevier; 2018:chap 52.