Dear Doctor: A friend of our family suddenly lost the vision in his left eye because of something called retinal artery occlusion. What is that? How do you protect against it?
Dear Reader: To answer your question, we should begin with a bit of anatomy. The retina is a layer of light-sensitive tissue that lines the back of the eye. Its job is to receive the incoming rays of light that pass through the lens and translate them into signals. These signals, or impulses, then travel along the optic nerve to the brain, which interprets them as the images we see. As with all tissues within the body, the retina needs a steady supply of blood to function properly. In the case of the retina, this comes primarily from an artery and a vein. If either of these vessels, or any of their smaller branches, become blocked, which is known as an occlusion, the retina sustains damage.
When a blockage occurs in the vein that serves the retina, the blood can’t drain away. Instead, it backs up and raises pressure within the eye, which can cause serious damage that affects sight. When the blockage occurs in the artery, as with your family friend, the retina is starved of oxygen and nutrients. Unless blood flow is restored quickly, the blockage will cause the cells of the retina to die. The result is a loss of vision. Unfortunately, there is no way to reverse the damage that arises as a result of retinal vessel occlusion.
One of the main causes of the condition is atherosclerosis, a disease in which fatty deposits known as plaques build up on the interior of the artery walls. These plaques can rupture and send debris into the bloodstream, which can potentially cause a full or partial blockage in another vessel. It makes sense, then, that the risk factors for atherosclerosis and for retinal vessel occlusion overlap. These include obesity, smoking, high cholesterol, high blood pressure and diabetes. Age is also a risk factor, with the majority of retinal vessel occlusions occurring in people who are 65 years of age and older. People living with a blood clotting disorder and those with glaucoma, which is chronically high pressure within the eye, are also at increased risk.
The same lifestyle changes that reduce the risk of atherosclerosis will also reduce the risk of retinal vessel occlusion, as well as diabetes, cardiovascular disease and stroke. A very important step is for smokers to quit. We know how difficult this is, so please ask your health care provider for help with crafting and sticking to a plan. Limit alcohol consumption and get regular exercise. Eat a diet that is high in fresh vegetables, leafy greens, fruits and lean meats and low in added salt, sugar and unhealthy fats. You don’t have to go for a halo here. We suggest our patients aim for 80% healthful eating. For those with health issues such as diabetes or hypertension, we tighten it up to 90% healthful eating.
Retinal vessel occlusion is a medical emergency. If you ever suddenly lose sight in one or both eyes, seek help immediately.
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