Diabetes can harm your eyes. It can damage the small blood vessels in your retina, the back part of your eye. This is called diabetic retinopathy.

Diabetes also increases your risk of having glaucoma, cataracts, and other eye problems.

Retinopathy - diabetic; Photocoagulation - retina; Diabetic retinopathy

Diabetic retinopathy is caused by damage to blood vessels of the retina. The retina is the layer of tissue at the back of the inner eye. It changes light and images that enter the eye into nerve signals that are sent to the brain.

Diabetic retinopathy is the leading cause of blindness in working-age Americans. People with type 1 and type 2 diabetes are at risk for this condition.

Watch this video about: Diabetes - retinal conditions

There are two stages of diabetic retinopathy:

• Nonproliferative develops first
• Proliferative is more advanced and severe

The chance of getting retinopathy and having a more severe form is greater when:

• You have had diabetes for a long time
• Your diabetes has been poorly controlled

Other problems that may develop are:

• Cataracts -- cloudiness of the eye lens
• Glaucoma -- increased pressure in the eye that can lead to blindness
• Macular edema -- blurry vision due to fluid leaking into the area of the retina that provides sharp central vision
• Retinal detachment -- scarring that may cause part of the retina to pull away from the back of your eyeball

Most often, diabetic retinopathy has no symptoms until the damage to your eyes is severe.

Symptoms of diabetic retinopathy include:

• Blurred vision and slow vision loss over time
• Floaters
• Shadows or missing areas of vision
• Trouble seeing at night

Many people with early diabetic retinopathy have no symptoms before major bleeding occurs in the eye. This is why everyone with diabetes should have regular eye exams.

The health care provider can diagnose diabetic retinopathy by dilating your pupils with eye drops and then carefully examining the retina. A retinal photography or fluorescein angiography test may also be used.

You may not know there is any damage to your eyes until the problem is very bad. Your doctor can catch problems early if you get regular exams. You will need to see an eye doctor who is trained to find and treat diabetic retinopathy.

Everyone with diabetes should have regular diabetic eye exams by an eye doctor who is skilled in the treatment of diabetic retinopathy.

If you have the early stage of diabetic retinopathy (nonproliferative), your health care provider may see:

• Blood vessels in the eye that are larger in certain spots (called microaneurysms)
• Blood vessels that are blocked
• Small amounts of bleeding (retinal hemorrhages) and fluid leaking into the retina

If you have more advanced retinopathy (proliferative), your health care provider may see:

• New blood vessels starting to grow in the eye that are fragile and can bleed
• Small scars forming on the retina and in other parts of the eye (the vitreous)

People with the earlier form (nonproliferative) of diabetic retinopathy may not need treatment. However, they should be closely followed by an eye doctor who is trained to treat diabetic eye diseases.

Once your eye doctor notices new blood vessels growing in your retina (neovascularization) or you develop macular edema, treatment is usually needed.

Several procedures or surgeries are the main treatment for diabetic retinopathy.

Laser eye surgery creates small burns in the retina where there are abnormal blood vessels. This process is called photocoagulation. It is used to keep vessels from leaking or to get rid of abnormal, fragile vessels.

A surgical procedure called vitrectomy is used when there is bleeding (hemorrhage) into the eye. It may also be used to repair retinal detachment.

Drugs that prevent abnormal blood vessels from growing, and steroid drugs injected into the eyeball are possible new treatments for diabetic retinopathy.

If you cannot see well:

• Make sure your home is safe so you do not fall
• Organize your home so that you can easily find what you need
• Get help to make sure you are taking your medicines correctly

American Diabetes Association - www.diabetes.org

National Diabetes Information Clearinghouse - www.diabetes.niddk.nih.gov

Prevent Blindness America - www.preventblindness.org

You can improve your outcome by keeping good control over your blood sugar and blood pressure.

Treatments can reduce vision loss. They do not cure diabetic retinopathy or reverse the changes that have already occurred.

Other problems that may develop are:

• Cataracts
• Glaucoma -- increased pressure in the eye that can lead to blindness
• Macular edema -- if fluid leaks into the area of the retina that provides sharp vision straight in front of you, your vision becomes more blurry
• Retinal detachment -- scarring may cause part of the retina to pull away from the back of your eyeball

Call for an appointment with an eye doctor (ophthalmologist) if you have diabetes and you have not seen an ophthalmologist in the past year.

Call your doctor if any of the following symptoms are new or are becoming worse:

• You cannot see well in dim light.
• You have blind spots.
• You have double vision (you see two things when there is only one).
• Your vision is hazy or blurry and you cannot focus.
• You have pain in one of your eyes.
• You are having headaches.
• You see spots floating in your eyes.
• You cannot see things on the side of your field of vision.
• You see shadows.

Tight control of blood sugar, blood pressure, and cholesterol is very important for preventing diabetic retinopathy.

Do not smoke. If you need help quitting, ask your doctor or nurse.

American Diabetes Association. Standards of medical care in diabetes--2012. Diabetes Care. 2012 Jan;35 Suppl 1:S11-63.

O'Doherty M, Dooley I, Hickey-Dwyer M. Interventions for diabetic macular oedema: a systematic review of the literature. Br J Opthalmol. 2008;92:1581-1590.

Diabetic Retinopathy Clinical Research Network (DRCR.net), Beck RW, Edwards AR, Aiello LP, Bressler NM, Ferris F, Glassman AR, et al. Three-year follow-up of a randomized trial comparing focal/grid photocoagulation and intravitreal triamcinolone for diabetic macular edema. Arch Ophthalmol. 2009;127:245-251.