High blood pressure affects a great many Americans. For one thing, men suffer from it at higher rates than women (47% vs. 43%), so your gender might play a factor in whether you’re at risk. This risk shouldn’t be ignored. In 2017, 500,000 people died with high blood pressure serving as a contributing cause.
Because it can be life-threatening, people do what they can to manage it. But one thing patients might not expect is the way it affects your eyes. Sometimes patients find that out during a routine eye exam, which isn’t ideal. High blood pressure, medication, or diseases with high blood pressure playing a part can all impact eye health, and it helps to know the risks early.
What is High Blood Pressure?
High blood pressure is a condition where blood pressure falls beyond healthy readings. Blood pressure tends to change very gradually and can have multiple underlying causes and effects.
Healthy blood pressure is 120/80mmHg. That’s 120 millimeters of mercury (mm Hg) over 80 millimeters) of mercury (mm Hg), which is an analog method of displaying pressure that has stuck. Pressure from your arm pushes a needle of mercury on a scale.
Left untreated, high blood pressure can lead to the heart’s tissues weakening, stretching out, and eventually to an often fatal condition called heart disease.
What is Blood Pressure?
Your heart pumps blood throughout the body by squeezing itself, pushing blood out into the veins. It’s a pressurized system, so there’s force acting on the inner walls of your veins. It’s on the veins, usually those of the arms, that doctors take pressure readings.
There are two pressure readings in a simple pump like your cardiovascular system:
The first is your systolic pressure, which is the higher pressure reading. It’s when your blood is being pushed along your veins by the compression of your heart. Again, a healthy adult should have no more than 120 mmHg.
The second reading is the diastolic pressure, which is quite a bit lower. It’s when the blood in your veins is at rest in between heartbeats. Again, a healthy adult should have no more than 80 mmHg.
How Changes in the Veins Impact Blood Pressure
One common cause of high blood pressure is fat or oil buildup in the arteries due to excessive sugar and fat consumption. It’s simple really: if the insides of your veins have a physical blockage, the pressure of the system can change. “By how much” can be a lot more complicated. But even very small veins in the back of your eyes can be affected by overall blood pressure.
To combat the effects of high blood pressure, doctors often prescribe hypertension medication.
High Blood Pressure Medication
High blood pressure meds are also known as hypertension medication. They have beta-blockers work in the bloodstream to counteract high blood pressure. But they can harm the lacrimal gland, leading to dry eye symptoms. Beta-blockers also seem to disrupt feeling in the cornea and can lead to overall eye irritation.
Dry Eye Side Effect
Dry eye can be a result of reduced tear quality or insufficient tear volume. Our eyes need a balance between mucus, water, and oil to stay lubricated, and this mix is called the tear film. If we are unable to produce enough tears or the tears we produce don’t contain the right combination, we feel the effects of dry eye.
As mentioned, the beta-blockers in hypertension medication unintentionally block signals from the brain from reaching the tear glands, so tear volume decreases. That upsets the proper tear film composition necessary for lubrication. Untreated dry eye can lead to cornea damage and chronic eye infections.
To adjust to dry eye as a result of medication, patients often benefit from dry eye therapy.
High Blood Pressure & Diabetes
There’s a term in the medical community called comorbidity, where two diseases often appear at the same time in the same patients. High blood pressure and diabetes are two conditions that appear to be comorbid. It’s unknown why, but they have a relationship. Furthermore, they seem to have the same causes:
- A diet high in fat and sodium
- Chronic inflammation
High blood pressure in tandem with diabetes can affect the eyes significantly. The retina has significantly more veins running through it than clearer parts of the eye, so blood pressure begins to change this critical and delicate vision component.
High blood pressure’s effects are much more pronounced with diabetes than without, which can lead to diabetic retinopathy and macular edema. Early detection becomes especially important.
Diabetes on its own can degrade your health, but the veins on the retina are at some of the highest risk with diabetes. These veins are crucial, so if they burst, multiply, or develop blockages, high blood pressure working with diabetes can seriously damage your sight.
Nonproliferative Diabetic Retinopathy (NPDR)
NPDR comes first in diabetic retinopathy, and your blood vessels develop tiny leaks. These leaks can lead to swelling of the macula, a light-sensitive part of the retina that renders faces, text, and other details. Sometimes veins stop short, so blood can’t bring oxygen to cells in the macula: a condition called macular ischemia.
With NPDR, your vision can be blurry. But macular swelling leads to diabetic macular edema (DME). When NPDR goes untreated, it can become proliferative diabetic retinopathy (PDR).
Proliferative Diabetic Retinopathy (PDR)
PDR is characterized by something called neovascularization. Pressure in the retina’s veins leads to the formation of new veins, which also begin leaking blood into the clear liquid chamber of the eye. Scar tissue can block images from hitting the macula or start separating the retina from the optic nerve.
Early detection helps you avoid this stage and severe damage to the retina. Key to managing your diabetes is monitoring NPDR and trying to keep it away from the PDR stage.
Diabetic Macular Edema (DME)
A swollen macula can lead to full or partial vision loss, especially your eyes’ detection of details like faces or text. Typically, symptoms include washed-out coloring and blurriness.
The fovea is the all-important center of the macula, and when edema swelling reaches the fovea, DME ends up becoming clinically significant macular edema (CSME). Sadly, DME can develop at any stage of diabetic retinopathy, so early detection becomes that much more important.
Diabetes & Your Eyes
Those with diabetes have their own needs, and eye exams should be centered around eye risk factors specific to diabetes. To that end, diabetic eye exams include careful retinal imaging stages, including Optos, fundoscopic exams, and optical coherence tomography (OCT) — the mix of which provides microscopic, wide-angle views of the retina to reveal early bleeding or small fluid buildup in the retina.
Keep Your Eyes in Mind
Your eye health is an important part of your overall health. Whether you have high blood pressure or not, it’s important to have regular eye exams.