blur vision in diabetic patient is due to????????? plz explain briefly

Diabetes affects virtually all structures of the eye, but it is important to know that some conditions found in people with diabetes are not an indication that eye disease will progress to permanent vision loss or blindness.

For example, many people experience blurred vision in the early stages of diabetes. This blurred vision is caused by fluid seeping into the lens of the eye and causing the lens to swell, changing its shape and altering its ability to focus properly. Once diabetes treatment begins and blood glucose is under control, the lens resumes its normal shape and vision improves.

Blurred vision also can occur early in insulin treatment or with fluctuating blood glucose levels. Again, fluids in the body are shifting, and fluid may enter or leave the lens. If you have this condition, be patient. The condition is not permanent and usually lasts only a few days or weeks. As you gain control of your diabetes and blood glucose gets closer to normal, your vision should improve. Therefore, unless you are really having functional difficulty due to poor vision, it is usually recommended that you wait until your blood glucose level settles and your vision stabilizes before getting or changing an eyeglass prescription.

Some eye problems you may experience can happen to anyone, with or without diabetes. For example, you might look into a mirror and see a bright red, pie-shaped wedge in the white of your eye. This is called subconjunctival hemorrhage. It occurs when a tiny blood vessel somehow breaks beneath the clear outside covering of the eyeball. This condition is not caused by diabetes – anyone can have it. It is a minor problem, and if left alone, usually disappears with in a week.

Similarly, anyone can get glaucoma, which is caused by too much pressure in the eye; this pressure damages your eye’s main nerve – the optic nerve. In fact, everyone past age 40 is at risk for glaucoma. However, a person with diabetes may be nearly twice as likely to get glaucoma as other adults. Glaucoma usually causes no symptoms, but in some cases, people experience vision loss or see bright haloes or colored rings around light. An ophthalmologist or optometrist can diagnose glaucoma by measuring eye pressure and with other simple tests. If detected, glaucoma can be treated with prescription eye drops that cause proper fluid exchange or with laser treatments or other surgery if necessary. Left untreated, glaucoma can progress and cause irreversible eye damage.

Another problem that anyone can develop is cataracts, a condition in which the lens of the eye becomes clouded, blocking the transmission of light. This problem usually comes with advancing age, and everyone is at risk. People with diabetes, however, are more likely to develop cataracts at a younger age. Poor diabetes control can speed up the process of developing cataracts. Eye doctors can treat cataracts with surgery. Traditionally, patients have worn thick eyeglasses or contact lenses that help the eye focus after surgery. Today, doctors routinely implant artificial lenses within the eye.

All of the above conditions can occur in anyone, whether one has diabetes or not. But there are some serious eye problems that are directly related to poorly controlled diabetes.

Chronic elevation of blood glucose level leads to damage of blood vessels (angiopathy). The endothelial cells lining the blood vessels take in more glucose than normal, since they do not depend on insulin. They then form more surface glycoproteins than normal, and cause the basement membrane to grow thicker and weaker. In diabetes, the resulting problems are grouped under "microvascular disease" (due to damage to small blood vessels) and "macrovascular disease" (due to damage to the arteries).

Damage to the eyes, known as diabetic retinopathy, is caused by damage to the blood vessels in the retina of the eye, and can result in gradual vision loss and potentially blindness. Diabetic retinopathy, growth of friable and poor-quality new blood vessels in the retina as well as macular edema (swelling of the macula), which can lead to severe vision loss or blindness.