Read and translate the text. Discuss the following items. Influence of diabetes mellitus on vision.
Importance of blood sugar control.
Ways of preventing blindness due to diabetes.
Diabetic Eye Disease
Diabetes mellitus is one of the leading causes of irreversible blindness worldwide. Diabetes mellitus may cause a reversible, temporary blurring of the vision, or it can cause a severe, permanent loss of vision.
Some people may not even realize they have had diabetes mellitus for several years until they begin to experience problems with their eyes or vision. Severe diabetic eye disease most commonly develops in people who have had diabetes mellitus for many years and who have had little or poor control of their blood sugars over that period of time.
The primary part of the eye affected by diabetes mellitus is the retina. In people with diabetes mellitus, changes in the walls of the small blood vessels in the retina are caused by blood sugar abnormalities. These small blood vessels may begin to “balloon,” forming microaneurysms, as well as oedema and haemorrhages into the retina. This process is called background diabetic retinopathy or nonproliferative diabetic retinopathy. If fluid accumulates in the central part of the retina (the macula) and causes swelling, the process is called diabetic macular oedema. As a response to decreased oxygen delivery to the retina, new blood vessels may begin to grow, a process called proliferative diabetic retinopathy. The new blood vessels are extremely leaky and fragile, potentially leading to bleeding inside the eye (vitreous haemorrhage) and usually resulting in severe vision loss. If not treated appropriately, this vision loss may be permanent. If the new blood vessels are extensive, they may cause scarring inside the eye.
Many people with diabetes mellitus may notice that their vision becomes blurry when they have rapid shifts in their blood sugar levels. Sugar in the blood can diffuse into the lens of the eye and cause it to swell, thus changing the focal point of the eye and resulting in blurring of the vision. Over time, this repeated swelling of this type is thought to damage the lens and cause it to become cloudy, resulting in a cataract.
The high blood sugar levels may also eventually damage the cells lining the trabecular meshwork toward the front of the eye, where the aqueous humour flows out from within the eye. When these cells are damaged, the trabecular meshwork cannot function correctly. If the trabecular meshwork does not function correctly, the fluid cannot flow out of the eye properly and the pressure inside the eye can increase. This high pressure inside the eye can damage the optic nerve and cause permanent vision loss. This process is called glaucoma.
Even if the patient has background diabetic retinopathy or early proliferative diabetic retinopathy, it is possible that they may not have any symptoms, or they may experience mild-to-severe blurring or vision loss. Many people with severe diabetic eye disease may not realize that they have a vision problem until it is too late and permanent damage has already occurred. Even if the patient is not experiencing any symptoms due to diabetes mellitus, the patient should have an annual eye examination by an ophthalmologist.