Islets of Hope  complications of diabetes

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Article disclaimer

Edited by Lahle Wolfe


Excerpts from the following articles

NIH Publication No. 04–4279, February 2004;

and Wikipedia

IOH Health Tip:  To reduce the risk of eye problems keep your blood glucose, blood pressure, and cholesterol under control.

For information about blindness and products designed for those who are visually impaired with diabetes please visit our "Blindness" webpage.

Frequently Asked Questions about Diabetic Retinopathy (Copyright © Prevent Blindness America)

Did you Know?

... That diabetic retinopathy can occur even in those with pre-diabetes?

Prolonged periods of high blood sugar levels cause damage to the small blood vessels in the retina at the back of the eye.

These blood vessels initially become leaky, and then may become blocked off.  This causes haemorrhages (spots of blood) and exudates (proteins) from the blood vessels on to the retina. It may also cause swelling, known as oedema of the retina.

The blocked vessels can starve the retina of oxygen, leading to the growth of new abnormal vessels from the retina.

Keeping your blood glucose in range will dramatically reduce the risk of all diabetes complications including problems with your eyes!

For More Information

Eye Care Professionals (ophthalmologists, optometrists)

Visit American Academy of Ophthalmology on the Internet at and click on "Find an Eye M.D."

Look for the American Optometric Association on the Internet at and click on the public website and then "Find an Optometrist" or call the AOA Diabetes Hot Line at 1–800–262–3947.

To get more information about taking care of diabetes, contact

National Diabetes Information Clearinghouse
1 Information Way
Bethesda, MD 20892–3560
Phone: 1–800–860–8747
Fax: 703–738–4929

National Diabetes Education Program
1 Diabetes Way
Bethesda, MD 20892–3600
Phone: 1–800–438–5383
Fax: 703–738–4929

American Diabetes Association
1701 N Beauregard  St.
Alexandria, VA 22311
Phone: 1–800–342–2383

Diabetes Teachers (nurses, dietitians, pharmacists, and other health professionals)

To find a diabetes teacher near you, call the American Association of Diabetes Educators toll-free at 1–800–TEAMUP4 (1–800–832–6874), or look on the Internet at and click on "Find a Diabetes Educator."


To find a dietitian near you, call the American Dietetic Association toll-free at 1–800–366–1655, or look on the Internet at and click on "Find a Nutrition Professional."


The National Eye Institute (NEI) is part of the National Institutes of Health. To learn more about eye problems, write or call NEI, 2020 Vision Place, Bethesda, MD 20892–3655, 301–496–5248; or see on the Internet.

MedLine Plus

Information on symptoms, prevention, tests, and treatment for diabetic retinopathy.

Support Groups

Prevent Blindness America

Nat'l Federation of the Blind Diabetes Action Network

Q&A from Ask The Doctor Forums:

Diabetic retinopathy (Diabetes Forum)

Diabetic retinopathy & flying (Diabetes Forum)

Retinopathy and optic nerve swelling
(Diabetes Forum)

Vitrectomy, daibetic
retinopathy (Diabetes Forum)

Blindness caused by diabetes. (Diabetes Forum

Scheiner, CDE
Think Like a Pancreas:    IOH Rating 5/5    Many books offer advice on managing diabetes, but few focus specifically on the day-to-day issues facing those who use insulin.  Scheiner, a certified diabetes educator and himself an insulin user himself since 1985, gives you the tools to "think like a pancreas; "that is, to successfully master the art and science of matching insulin to the body’s ever-changing needs.    Read IOH Book Reviews


islets of hope diabetes medical library                      back to main "Complications" page
Complications of Diabetes

Diabetic Retinopathy
Symptoms, Causes, Treatment & Prevention

Mini Site Index
What is Diabetic Retinopathy?
Risk Factors
Causes of Diabetic Retinopathy
Signs and Symptoms
How can diabetes hurt my eyes?
How can diabetes hurt the retinas of my eyes?
What happens as diabetes retina problems get worse?
What can I do about diabetes retina problems?
Does diabetes cause other eye problems?
What can I do to prevent diabetes eye problems?
For More Information

What is Diabetic Retinopathy?

Retinopathy is a general term that refers to some form of non-inflammatory damage to the retina of the eye. Most commonly it is a problem with the blood supply that is the cause for this condition. Frequently, retinopathy is an ocular manifestation of systemic disease.

Diabetic retinopathy is retinopathy (damage to the retina) caused by complications of diabetes mellitus, which could eventually lead to blindness. It is an ocular manifestation of systemic disease which affects up to 80% of all diabetics who have had diabetes for 15 years or more.  

Risk factors

All people with diabetes mellitus are at risk (type 1 and type 2 diabetes). The longer a person has diabetes, the higher the risk of developing some ocular problem.

During pregnancy, diabetic retinopathy may also be a problem for women with diabetes. It is recommended that all pregnant women with diabetes have dilated eye examinations each trimester to protect their vision.  

Causes of  Retinopathy

  • diabetes causes diabetic retinopathy
  • arterial hypertension causes hypertensive retinopathy
  • prematurity of the newborn  causes retinopathy of prematurity (ROP)
  • sickle cell anemia
  • direct sunlight exposure causes solar retinopathy
  • medicinal products causes drug-related retinopathy
  • retinal vein or artery occlusion

Many types of retinopathy are progressive and may result in blindness or severe vision loss or impairment, particularly if the macula becomes affected.

Retinopathy is diagnosed by an optometrist or an ophhtalmologist during a form of eye examination called a fundus exam. Treatment depends on the cause of the disease.  

Signs and Symptoms

Diabetic retinopathy often has no early warning signs. Even macular edema, which may cause vision loss more rapidly, may not have any warning signs for some time. In general, however, a person with macular edema is likely to have blurred vision, making it hard to do things like read and drive. In some cases, the vision will get better or worse during the day.

As new blood vessels form at the back of the eye as a part of proliferative diabetic retinopathy (PDR), they can bleed (hemorrhage) and blur vision. The first time this happens, it may not be very severe. In most cases, it will leave just a few specks of blood, or spots, floating in a person's visual field, though the spots often go away after a few hours.

These spots are often followed within a few days or weeks by a much greater leakage of blood, which blurs vision. In extreme cases, a person will only be able to tell light from dark in that eye. It may take the blood anywhere from a few days to months or even years to clear from the inside of the eye, and in some cases the blood will not clear. These types of large hemorrhages tend to happen more than once, often during sleep.

You may not get any signs of diabetes retina damage or you may get one or more signs:

  • blurry or double vision
  • rings, flashing lights, or blank spots
  • dark or floating spots
  • pain or pressure in one or both of your eyes
  • trouble seeing things out of the corners of your eyes
normal eyechart blurry eyechart
If you have retina damage from diabetes, you may have blurry or double vision.


How can diabetes hurt my eyes?

High blood glucose and high blood pressure from diabetes can hurt four parts of your eye:

  1. Retina (REH-ti-nuh). The retina is the lining at the back of the eye. The retina's job is to sense light coming into the eye.

  2. Vitreous (VIH-tree-us). The vitreous is a jelly-like fluid that fills the back of the eye.

  3. Lens. The lens is at the front of the eye and it focuses light on the retina.

  4. Optic nerve. The optic nerve is the eye's main nerve to the brain.

Picture of eye showing lens, retina, blood vessels on retina, optic nerve, and vitreous

This is a picture of an eye from the side.

How can diabetes hurt the retinas of my eyes?

Retina damage happens slowly. Your retinas have tiny blood vessels that are easy to damage. Having high blood glucose and high blood pressure for a long time can damage these tiny blood vessels.

First, these tiny blood vessels swell and weaken. Some blood vessels then become clogged and do not let enough blood through. At first, you might not have any loss of sight from these changes. This is why you need to have a dilated eye exam once a year even if your sight seems fine.

One of your eyes may be damaged more than the other. Or both eyes may have the same amount of damage.

Diabetic retinopathy (REH-tih-NOP-uh-thee) is the medical term for the most common diabetes eye problem.  

What happens as diabetes retina problems get worse?

As diabetes retina problems get worse, new blood vessels grow. These new blood vessels are weak. They break easily and leak blood into the vitreous of your eye. The leaking blood keeps light from reaching the retina.

You may see floating spots or almost total darkness. Sometimes the blood will clear out by itself. But you might need surgery to remove it.

Over the years, the swollen and weak blood vessels can form scar tissue and pull the retina away from the back of the eye. If the retina becomes detached, you may see floating spots or flashing lights.

You may feel as if a curtain has been pulled over part of what you are looking at. A detached retina can cause loss of sight or blindness if you don't take care of it right away.

Call your doctor right away if you are having any vision problems or if you have had a sudden change in your vision.

Picture of eye showing no diabetes damage.
Picture of eye showing some diabetes damage.
Picture of eye showing a lot of diabetes damage.

What can I do about diabetes retina problems?

First, keep your blood glucose and blood pressure as close to normal as you can.

Your eye doctor may suggest laser treatment, which is when a light beam is aimed into the retina of the damaged eye. The beam closes off leaking blood vessels. It may stop blood and fluid from leaking into the vitreous. Laser treatment may slow the loss of sight.

If a lot of blood has leaked into your vitreous and your sight is poor, your eye doctor might suggest you have surgery called a vitrectomy (vih-TREK-tuh-mee). A vitrectomy removes blood and fluids from the vitreous of your eye. Then clean fluid is put back into the eye. The surgery often makes your eyesight better.  

Does diabetes cause other eye problems?

Yes. You can get two other eye problems—cataracts and glaucoma. People without diabetes can get these eye problems, too. But people with diabetes get them more often and at a younger age.

  • A cataract (KA-ter-act) is a cloud over the lens of your eye, which is usually clear. The lens focuses light onto the retina. A cataract makes everything you look at seem cloudy. You need surgery to remove the cataract. During surgery your lens is taken out and a plastic lens, like a contact lens, is put in. The plastic lens stays in your eye all the time. Cataract surgery helps you see clearly again.

  • Glaucoma (glaw-KOH-muh) starts from pressure building up in the eye. Over time, this pressure damages your eye's main nerve—the optic nerve. The damage first causes you to lose sight from the sides of your eyes. Treating glaucoma is usually simple. Your eye doctor will give you special drops to use every day to lower the pressure in your eye. Or your eye doctor may want you to have laser surgery.  


Diabetic retinopathy is detected during an eye examination that includes:

  • Visual acuity test. This test uses an eye chart to measure how well a person sees at various distances (i.e., visual acuity).
  • Pupil dilation. The eye care professional places drops into the eye to widen the pupil. This allows him or her to see more of the retina and look for signs of diabetic retinopathy. After the examination, close-up vision may remain blurred for several hours.
  • Ophthalmoscopy. This is an examination of the retina in which the eye care professional: (1) looks through a device with a special magnifying lens that provides a narrow view of the retina, or (2) wearing a headset with a bright light, looks through a special magnifying glass and gains a wide view of the retina. Note that hand-held ophthalmoscopy is insufficient to rule out significant and treatable diabetic retinopathy.
  • Tonometry.  A standard test that determines the fluid pressure (intraocular pressure) inside the eye. Elevated pressure is a possible sign of glaucoma, another common eye problem in people with diabetes.
  • Digital Retinal Screening Programs.  Systematic programs for the early detection of eye disease including diabetic retinopathy are becoming more common. This involves digital image capture and transmission of the images to a digital reading center for evaluation and treatment referral.

The eye care professional will look at the retina for early signs of the disease, such as: (1) leaking blood vessels, (2) retinal swelling, such as macular edema, (3) pale, fatty deposits on the retina – signs of leaking blood vessels, (4) damaged nerve tissue (neuropathy), and (5) any changes in the blood vessels.

Should the doctor suspect the need treatment for macular edema, he or she may perform a test called fluorescein angiography. In this test, a special dye is injected into the arm. Pictures are then taken as the dye passes through the blood vessels in the retina. This test allows the doctor to find the leaking blood vessels.  


There are two major treatments for diabetic retinopathy, which are very effective in reducing vision loss from this disease. In fact, even people with advanced retinopathy have a 90 percent chance of keeping their vision when they get treatment before the retina is severely damaged. Still, the best way of addressing diabetic retinopathy is to monitor it vigilantly and ensure that it does not happen in the first place by careful blood glucose control and limitation of dietary fructose.

These two treatments are laser surgery and vitrectomy. It is important to note that although these treatments are very successful, they do not cure diabetic retinopathy.

Laser surgery

A type of laser surgery called panretinal photocoagulation, or PRP, is used to treat severe macular edema and proliferative retinopathy. The goal is to create 1 000 - 2 000 burns in the retina with the hope of reducing the retina's oxygen demand, and hence the possibility of ischemia. In treating advanced diabetic retinopathy, the burns are used to destroy the abnormal blood vessels that form at the back of the eye.

Before the surgery, the ophthalmologist dilates the pupil and applies anesthetic drops to numb the eye. In some cases, the doctor also may numb the area behind the eye to prevent any discomfort. The lights in the office are also dimmed to aid in dilating the pupil. The patient sits facing the laser machine while the doctor holds a special lens to the eye. During the procedure, the patient may see flashes of light. These flashes may eventually create an uncomfortable stinging sensation for the patient. After the laser treatment, patients should be advised not to drive for a few hours while the pupils are still dilated. Vision may remain a little blurry for the rest of the day, though there should not be much pain in the eye.

Scatter laser treatment

Rather than focus the light on a single spot, the eye care professional may make hundreds of small laser burns away from the center of the retina, a procedure called scatter laser treatment. The treatment shrinks the abnormal blood vessels. Patients may lose some of your side vision after this surgery, but the procedure saves the rest of the patient's sight. Laser surgery may also slightly reduce color and night vision.

A person with proliferative retinopathy will always be at risk for new bleeding. This means that multiple treatments may be required to protect vision.


Instead of laser surgery, some people need an eye operation called a vitrectomy to restore vision. A vitrectomy is performed when there is a lot of blood in the vitreous. It involves removing the cloudy vitreous and replacing it with a saline solution made up of salt and water. Because the vitreous is mostly water, there should be no change between the saline solution and the normal vitreous.

Studies show that people who have a vitrectomy soon after a large hemorrhage are more likely to protect their vision than someone who waits to have the operation. Early vitrectomy is especially effective in people with insulin-dependent diabetes, who may be at greater risk of blindness from a hemorrhage into the eye.

Vitrectomy is often done under local anesthesia. The doctor makes a tiny incision in the sclera, or white of the eye. Next, a small instrument is placed into the eye to remove the vitreous and insert the saline solution into the eye.

Patients may be able to return home soon after the vitrectomy, or may be asked to stay in the hospital overnight. After the operation, the eye will is red and sensitive, and patients usually need to wear an eyepatch for a few days or weeks to protect the eye. Medicated eye drops are also prescribed to protect against infection.  

Image of eye showing lens, retina, blood vessels on retina, optic nerve, and vitreous.
High blood glucose can cause eye problems.

What can I do to prevent diabetes eye problems?

  • Keep your blood glucose and blood pressure as close to normal as you can.

  • Have an eye doctor examine your eyes once a year. Have this exam even if your vision is OK. The eye doctor will use drops to make the black part of your eyes (pupils) bigger. This is called dilating (DY-lay-ting) your pupil, which allows the doctor to see the back of your eye. Finding eye problems early and getting treatment right away will help prevent more serious problems later on.

dilated eye   undilated eye
 Dilated eye
 Undilated eye
  • Ask your eye doctor to check for signs of cataracts and glaucoma. (See Does diabetes cause other eye problems? to learn more about cataracts and glaucoma.)

  • If you are pregnant and have diabetes, see an eye doctor during your first 3 months.

  • If you are planning to get pregnant, ask your doctor if you should have an eye exam.

  • Don't smoke.


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Page Updated 05/08/2006