By Martha Funnell, MS, RN, CDE
One of the biggest fears among people with diabetes is losing their eyesight. While it is true that diabetes is still a leading cause of blindness, it happens much less often than it did in the past. It is less common because we know more about prevention, it can be detected earlier and the treatments work better than they did before.
Four Ways Diabetes Affects Your Eyes
1. Blurred vision occurs when your blood glucose is too high, which causes the lens of the eye to swell. The blurred vision usually gets better when your blood glucose is back in the target range, but it may take as long as three months.
2. Cataracts generate a cloudy spot in the lens of the eye. The lens is made up of proteins and water and is usually clear. But if the proteins clump together, a cloudy spot forms, and light can no longer pass through. Symptoms include blurry vision, poor night vision, difficulty distinguishing colors and problems with glare. Keeping your blood glucose close to normal, wearing sunglasses when you are outside and not smoking can help prevent cataracts.
3. Glaucoma is a condition in which there is too much fluid inside the eye, leading to a buildup of pressure in the eye. If not treated, the increased pressure can damage the nerves in the eye and cause loss of vision. Glaucoma is usually treated with eye drops.
4. Retinopathy refers to damage to the retina, a structure at the back of the eyeball that sends the pictures of what we see to the brain. Damage to the retina occurs when small blood vessels in the eye are harmed by high blood glucose. The central part of the retina is called the macula. The macula is a tiny area that provides extra sharp vision.
TYPES OF RETINOPATHY
Over time, high blood glucose and blood pressure levels cause the small blood vessels in the retina to become weak. As blood flows through the damaged vessels, small pouches balloon out where there are weak places. Because these pouches are fragile, they can break easily, causing blood to leak into the retina. Scars form over the places where the vessels break. There is usually no change in sight unless the macula is affected.
The small blood vessels in the retina can become completely blocked. In an effort to keep the blood flowing, new blood vessels grow around the blocked vessels. The new blood vessels grow over the retina and into the clear jelly that fills the eyeball, called the vitreous. Because the new blood vessels are fragile, they can break and leak blood into the vitreous. You may feel as though you are looking through a spider web or through fog,see black floating spots or lose sight in one eye. If this happens, you need to get help immediately.
Laser therapy is used to seal or destroy the weak places in the small blood vessels that break or leak.
A vitrectomy is surgery done to remove the clear jelly that fills the eyeball and remove any blood or scar tissue. The clear jelly is replaced with clear fluid. This surgery is only done when sight has been lost in one eye. Sometimes vision will return after the operation.
preventing dAmAge to your eyes
Most of the damage in retinopathy is caused by high levels of glucose being forced through the very tiny blood vessels in the back of the eye. You can prevent damage or keep it from getting worse by keeping your blood glucose and blood pressure in your target range. There usually are no early signs and symptoms of retinopathy. The only way to find out if you have any signs of retinopathy is to have your eyes dilated and examined by an eye care professional. Drops are placed in the eye to dilate the pupils so they can be seen clearly. It is not painful, but be sure to take sunglasses with you to your appointment because bright lights can be slightly painful when your pupils are dilated. This should be done once a year. Ask your doctor for a referral if you have never had an eye exam or it has been more than one year.