Why does diabetes affect your eyes?
Eye complications are very common with people who suffer from diabetes. While some people with diabetes will develop blindness, most will suffer minor eye complications. The earlier eye problems are discovered, the more likely they will not become serious.
Almost everyone with diabetes will at some time have some form of retinopathy which is a disorder of the retina. There are two forms of retinopathy: nonproliferative and proliferative. Nonproliferative retinopathy is the most common. When this happens, capillaries in the back of the eyes balloon, forming pouches. Proliferative retinopathy is a very serious condition that takes several years to progress. Blood vessels become very damaged and close off. Because of this, new, weaker blood vessels form and leak blood. This causes what is called a vitreous hemorrhage.
Also, people with diabetes are 40% more likely to develop glaucoma. This occurs when pressure builds up in the eyes. Vision decreases because the retina and nerves become damaged.
In addition, people with diabetes are 60% more likely to develop cataracts. Cataracts is caused when the lens of the eye turns cloudy.
Diabetes mellitus is one of a few disease processes that have detrimental affects on every organ system in the body. Diabetic retinopathy affects the retina of the eye. The retina is the inner most layer of the eye. Nerve fibers from the retina exit the eye posteriorly and form the optic nerve. DM affects the eyes because increased blood glucose levels over time damage the optic nerve. The optic nerve is damaged because it has been deprived of glucose. In DM, circulating glucose doesn't enter cells, it stays in the CV system. Nerves need a constant supply of glucose but with DM the supply is deficient. Another reason DM affects eye sight is because high blood glucose concentrations over time also adversely damage the blood vessels that supply the eye with blood.
Because diabetes affects so many systems around the body, particularly those having anything to do with the processing, absorption or excretion of sugars, it can have effects all over the body. It generally starts to have these effects because the concentration of glucose is higher than it ought to be.
Prolonged high levels of glucose begin to have an effect on the eyes as the lenses of the eyes actually begin to absorb glucose and this in turn starts to change the actual shape of the lenses causing rapid and dizzying changes in vision.
Diabetes causes problems in the retina with what are collectively called microvascular abnormalities. The small blood vessels develop microaneurysms and leak blood. New blood vessel growth (neovascularization) occurs. Unfortunately, these blood vessels are weak and also leak. These leaks (hemorrhages) can cause irreversible damage to the retina, with subsequent vision loss.