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| Causes Of Diabetic Retinopathy |
Damage to the retina from high blood sugar occurs when microaneurysms form on the walls of the small blood vessels. The vessel walls become porous, leaking fluid into the retina. Extensive leakage can leave deposits of fatty material in the retina. When swelling happens in the macula, vision may be reduced or blurred.
As vessel walls weaken, the blood vessels may close off, reducing blood flow and depriving the retina of oxygen. This can trigger proliferative diabetic retinopathy, when the oxygen-starved retina grows new blood vessels. Unfortunately, these new blood vessels don't resupply the retina with a normal blood flow. Instead they may produce other complications:
Vitreous hemorrhage. The new blood vessels may bleed (hemorrhage) into the vitreous. If the amount of bleeding is small, you might see only a few dark spots or floaters. In more severe cases, blood can completely fill the vitreous cavity and block all of your vision. Vitreous hemorrhage by itself usually doesn't cause permanent vision loss. The blood eventually clears from the eye - usually within a few months - and your vision returns to its previous clarity, unless the retina is damaged.
Traction retinal detachment. The new blood vessels are often accompanied by the growth of scar tissue. The scar tissue eventually shrinks. As it shrinks it pulls the retina away from the back wall of the eye. This causes blank or blurred areas in your field of vision.
Neovascular glaucoma. The proliferation of blood vessels on the retina may be accompanied by the growth of abnormal new blood vessels on the iris. This can interfere with the normal flow of fluid out of the eye and cause pressure in the eye to build up. The result is neovascular glaucoma, a serious complication of diabetic retinopathy that can cause pain, vision loss and, if not treated successfully, the loss of the eye.
Risk factors
People with diabetes are at risk of retinopathy, whether they have type 1 or type 2 diabetes. Their risk increases the longer they have the disease. This puts people with type 1 diabetes at especially high risk because they usually become diabetic at a young age. If you were over 30 when you first got diabetes, your risk is lower, but for some people in this group, retinopathy may be the first sign of diabetes. Whatever your age, if you need to take insulin, your risk of retinopathy is higher. Other risk factors for diabetic retinopathy include:
- Poorly controlled blood sugar levels.
- Kidney disease.
- High blood pressure.
- High blood fats (elevated levels of low-density lipoprotein cholesterol and triglycerides).
- Pregnancy. Women with type 1 diabetes who become pregnant have about a 10 percent risk of developing NPDR. Women who already have NPDR when they become pregnant tend to experience a progression of the disease, although it may improve after delivery. Less than 10 percent of pregnant women with mild NPDR develop PDR.
- Obesity.
- Infections.
Blurred vision is commonly brought on by fluctuations in blood sugar. Prolonged periods of excessive blood sugar cause sugar and its breakdown products to accumulate in the lens. This accumulation sucks up water and makes the lens swell, resulting in nearsightedness - meaning distant objects appear blurry to you. The nearsightedness subsides once your blood sugar is brought under steady control.
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| Causes Of Diabetic Retinopathy |
Blurred vision can also be caused by macular edema or swelling, regardless of your blood sugar level. This is cause for greater concern because macular edema often develops in people with diabetic retinopathy. The swelling may fluctuate during the day, making your vision get better or worse. If blood vessels in your eye are hemorrhaging, you might notice spots floating in your field of vision temporarily. These small spots are often followed within a few days or weeks by larger spots or clouds, which are caused by more massive hemorrhaging. To find out more, you can check out Causes Of Diabetic Retinopathy.