How Does Your Heart and Blood Vessels Affect Your Eyes?

Your eyes have one of the most intricate circulatory patterns throughout the entire body. They are fed and drained by numerous blood vessels that provide nutrients to the different components of the eye.

Unfortunately, systemic conditions that affect blood flow can have major and permanent effects on the visual system, having the potential to cause vision loss. This article provides a brief description of the blood flow within the eye and discusses some of the main conditions that can affect the eye.

Ocular Blood Flow

Oxygenated blood provides nutrients to the eye through two major routes. Within the eye is the central retinal artery, which provides nutrients to the inner portion of the retina, the nerve layer at the back of the eye.

The choroid route supplies the rest of the eye (i.e. the outer portion of the retina, iris, optic nerve, etc.). Subsequently, the eye is drained by the veins that eventually join with blood coming from the rest of the head and brain.

Diabetes and Your Blood Vessels

Individuals with diabetes are at risk for diabetic retinopathy. This is associated with increased blood sugar levels that weaken the blood vessel walls within the nerve layer at the back of the eye.

The damage to the blood vessels can lead to leakages of blood into the tissue. In addition, fluid can accumulate at the back of the eye and cause swelling, most often in the macula.

This location is particularly important for an individual’s central vision and clarity. In mild to moderate cases, this condition can often be managed with proper control of blood sugar levels through medications or insulin pumps.

In more severe cases, new blood vessels can form to help increase blood flow to the area. This is known as neovascularization and has the potential to cause other ocular conditions such as retinal detachments.

In these cases, intravitreal injections into the eye may be necessary for treatment.

Atherosclerosis – A Blood Vessel Disorder

This refers to a condition in which the volume within a blood vessel narrows, leading to a blockage of blood flow. This could be due to causes such as high cholesterol levels or blood clots.

In the eyes, blood vessels can also be blocked and certain areas may lack proper delivery of oxygen and nutrients. It can be as severe as the main artery being disrupted, which can lead to irreversible vision loss, or a small artery with the eye that has minimal effect as there are other arteries to provide nutrients in its place.

In some cases, the vision loss can also be temporary, returning after the systemic condition has been dealt with through medical procedures or medication.

Age-Related Macular Degeneration

Age-related macular degeneration, or ARMD, refers to a condition in which the macula (a spot in the nerve layer responsible for central, detailed vision) is disrupted by drusen. The blood flow becomes relevant in cases of wet ARMD, which refers to the stage of ARMD when the membrane that lies beneath the nerve layer is broken and blood is coming through. This is often treated with an intravitreal injection.

Glaucoma

Last but not least, we will be discussing glaucoma and why the blood flow can affect it. In some cases of glaucoma, such as normal tension glaucoma, the blood pressure can be a risk factor.

Those with low blood pressure are at risk for a type of glaucoma that is believed to occur due to the pressure imbalance between the blood flow and the pressure within the eye. A normal pressure within the eye may appear “high” if the pressure outside of the eye is low, thus putting an individual at risk for normal tension glaucoma.