People with type 2 diabetes develop cataracts due to their high levels of blood sugar. "As the blood sugar levels increase, the concentration of [glucose] around the lens goes up," Gonzalez says. "The sugar enters the lens through osmosis, bringing water with it." That changes the chemical composition inside the lens, prompting the lens to grow cloudy.
People with type 2 diabetes also are 40 percent more likely to develop another common eye disease, glaucoma. Glaucoma occurs due to an increase in fluid pressure inside the eyeball. The pressure pinches off blood flow to the retina and optic nerve, causing slow damage. This damage leads to gradual but permanent vision loss.
Diabetes: Protect Your Vision :
The problems with blood sugar are the principal cause of the damage to the eye," Gonzalez says. "Most people with diabetes will vary in terms of how high their high is and how low their low is. The larger the difference between the high and the low, the more susceptible you are to damage from diabetes." Tightly managing your type 2 diabetes is the best way to prevent eye health complications.
By Dennis Thompson, Jr. Reviewed by Farrokh Sohrabi, MD
Type 2 diabetes can have a terrible impact on your eye health. Learn about the major diabetic eye diseases and get tips for avoiding them.
Typr 2 diabetes is a systemic disease, and if left untreated it can cause many serious complications in areas throughout the body — including the eyes. In fact, complications that threaten eye health are among the leading problems that can occur with diabetes and put people with type 2 diabetes at a greater risk of blindness. Preventing eye problems such as diabetic retinopathy, cataracts, and glaucoma hinges, in large part, on successfully managing blood sugar levels.
Unchecked blood sugar levels that spike and plummet can cause damage to the blood vessels of the eyes, resulting in a condition known as diabetic retinopathy. This is the most common vision problem due to diabetes. Retinopathy targets the retina, the tissue lining the back of the eye wall that perceives the images captured by the eye.
There are two main types of diabetic retinopathy:
Non-proliferative retinopathy. This is the disease's first stage. "The fluctuations in the blood sugar begin to damage the walls of blood vessels," says Victor H. Gonzalez, MD, founder of Valley Retina Institute in McAllen, Texas, and a volunteer for the American Diabetes Association. "The blood vessels begin to leak." The leakage causes the retina to swell, blurring your vision and causing straight lines to appear wavy as the retina takes on an uneven shape.
Proliferative retinopathy. This is the disease's second stage, in which the eye tries to compensate for the loss of blood vessels by forming new ones. These new blood vessels are weak, though, and crowd into the retina. "Unfortunately, the blood vessels begin to grow around the central vision," Dr. Gonzalez says. As these vessels mature, they often bleed and cause scarring that can lead to a tractional retinal detachment, which occurs when the scar tissue causes the retina to pull away from the eye tissue. This can cause blindness if not corrected.
Cataracts and Glaucoma :
Early detection is also key to preventing vision loss, especially for diabetic retinopathy and glaucoma. People with diabetes should undergo a thorough eye examination once a year. These eye examinations must involve dilation of the pupil. That's the only way an eye doctor can observe the back of the eye.
"They need to have a dilated eye examination performed by an ophthalmologist," Gonzalez says. "Sometimes patients will go to health fairs and have an eye screening there. That's not a diabetic eye exam. Unfortunately, I've had some people get into trouble because they use that as their annual eye examination."
"We have very effective treatments," Gonzalez adds. "If we begin treatment early on in these patients, we can have a very significant impact on their retinopathy and reduce their risk of severe vision loss.