Can Vision Be Affected By Hypertension?

Hypertension or high blood pressure is not only a common risk factor for heart disease, stroke and kidney disease but also capable of causing eye disease. Hypertension can damage the blood vessels in the retina, which is the area at the back of the eye where images focus. This can limit the retina’s function and put pressure on the optic nerve, thus causing vision problems. The condition is known as hypertensive retinopathy (HR) that can lead to blurred vision or the complete loss of sight. People with hypertension and diabetes are at an even greater risk for developing this condition.

Most people with HR do not have symptoms. It is usually discovered during a routine eye examination or until the condition has progressed extensively. Some possible signs and symptoms may include eye swelling, reduced vision, double vision accompanied by headaches, or vision loss.

The extent and severity of the retinopathy is generally represented on a scale of 1 to 4. In Grade 1, there is a mild narrowing of the retinal artery. Grade 2 is similar to Grade 1, but there is more severe or tighter constrictions of the retinal artery. This phenomenon is known as arteriovenous (AV) nipping. In additional to all the signs of Grade 2, Grade 3 also has retinal edema, microaneurysms, cotton-wool spots (fluffy white lesions on the retina), and retinal hemorrhages (bleeding). Grade 4 has severe signs of Grade 3 along with optic disc swelling called papilledema and macular edema. People with Grade 4 retinopathy have a higher risk for stroke and may have kidney or heart disease.

Patients with HR on the lower end of the scale may not have any symptoms, but for those on Grade 4, their optic nerve may begin to swell and cause more serious vision problems. High-grade retinopathy (Grade 3 and 4) tends to indicate serious blood pressure concerns and is associated with higher rates of stroke, heart attack, congestive heart failure and even death.

A study released in 2013 in journal ‘Hypertension’ reported that HR predicts the long-term risk of stroke, independent of blood pressure, even in treated patients with hypertension with good hypertension control. Another paper published in July 2008 in ‘Journal of vascular and interventional neurology’ suggested the presence of hypertensive retinal vascular changes is linked to higher risk of cardiovascular disease (heart disease and stroke).

Controlling and lowering hypertension with a combination of lifestyle changes and medications are the key for an effective treatment for HR. Lifestyle changes include adopting healthy diet, getting regular physical activity, and reducing salt intake. Smokers should kick the habit and those who are overweight should lose weight. Medications must be taken as prescribed by doctors. Last but not least, patients should go for regular medical examinations to ensure that their blood pressure readings are normal.

Assess Stroke Risk Through Eye!

High blood pressure, also known as hypertension, is not only a risk factor for heart disease but also the single most significant risk factor for stroke. Stroke occurs when blood flow stops flowing to the brain, either because of a clot or a hemorrhage.

Stroke is number 4 killer and a leading cause of disability in the United States. It is, however, merely impossible for doctors to predict which hypertensive patients are most likely to develop a stroke. Now, a simple eye examination might just provide that information.

A study revealed that retinal imaging, a non-invasive and cheap way of examining the blood vessels of the retina, might someday help assess whether a person is more likely to develop a stroke. Researchers from the National University of Singapore reported on August 12, 2013 in the American Heart Association journal ‘Hypertension’ that the retina provides information on the status of blood vessels in the brain.

For an average 13 years, researchers tracked occurrence of stroke in 2,907 patients with hypertension but had not experienced a stroke previously. Photographs of the retina of each participant were taken at baseline. Retina is the light-sensitive layer of cells at the back of the eyeball.

When high blood pressure damages blood vessels in the retina, a condition called hypertensive retinopathy occurs. On photographs, it will be scored as none, mild or moderate/severe.

146 participants experienced a stroke caused by a blood clot and 15 by bleeding in the brain (hemorrhage) during the follow-up period.

After adjusting for several stroke risk factors like age, sex, race, cholesterol levels, blood sugar, body mass index, smoking and blood pressure readings, the researchers found that the risk of stroke was 35 percent higher in those with mild hypertensive retinopathy and 137 percent higher in those with moderate or severe hypertensive retinopathy.

Even for patients who were on medication and achieving good blood pressure control, the risk of a blood clot was 96 percent higher in those with mild hypertensive retinopathy and 198 percent higher in those with moderate or severe hypertensive retinopathy. 

While the findings did add to previous research on the value of retinopathy as an indicator of small vessel disease and increased risk of stroke, the researchers felt that it is too early to recommend changes in clinical practice. Further studies are required to confirm their findings and examine if retinal imaging could be useful in offering additional information about stroke risk in people with high blood pressure.