Diabetes Mellitus (DM)

Did you know that diabetes:

  • is the leading cause of blindness in working-age Americans?
  • is the fourth most common cause of visual loss in people over age 55?
  • is responsible for 7% of legal blindness in those over age 65?

One is insulin dependent diabetes mellitus (IDDM), and this usually is diagnosed in adolescence.  The pancreas is an organ in the body that produces insulin, and sometimes people have a defective pancreas and are therefore not able to produce the necessary insulin to keep the body blood sugars regulated.  Insulin is the molecule that regulates blood sugar levels, and without it the blood sugar levels can increase to a dangerous level.  Excessive blood sugar levels will then go on to cause significant damage to every organ in the body.

Another type of diabetes is non-insulin dependent diabetes mellitus (NIDDM). This is often called adult-onset diabetes, as it is frequently diagnosed at a later stage of life (usually over the age of 30).  The ultimate problem is the same (poor regulation of blood sugars), but the body can still produce some insulin.  The insulin produced by the body is not sufficient for good blood sugar control, and people may take oral medications and/or insulin to help control the blood sugars and the blood sugar level resistance to the amount of insulin produced by the body. 

Over time, diabetes will damage all of the blood vessels throughout the body.  This can occur despite good blood sugar control, but certainly occurs quicker in people who have poor blood sugar control.  A person cannot tell if or when his or her ocular blood vessels are being affected.  Significant damage can occur in the ocular vessels even when vision is completely normal.  This is why a yearly eye exam is critical for everyone with diabetes.  The blood vessels within the eye are among the smallest blood vessels in the body, and therefore the early (microscopic) damage that diabetes causes to all blood vessels will show up first in the eye.  A person can have normal, 20/20 vision with significant damage to their ocular blood vessels without realizing it.  Only a diabetic examination by an eye doctor is able to tell if these blood vessels are damaged, and to what extent.  The damage to these retinal vessels is referred to as diabetic retinopathy.  Diabetic retinopathy changes can often be improved if the damage is not severe.  But, if left untreated and unchecked, diabetic retinopathy can lead to total and complete blindness. 

Did you know that diabetes:

  • is the leading cause of blindness in working-age Americans?
  • is the fourth most common cause of visual loss in people over age 55?
  • is responsible for 7% of legal blindness in those over age 65?

and most all of these eye problems are preventable with early diagnosis and management by an eye doctor!
At a minimum, every diabetic patient need an annual eye examination with dilation (or more frequently), regardless of how good their vision is doing.

Non-proliferative Diabetic Retinopathy

Non-proliferative diabetic retinopathy (NPDR), commonly known as background retinopathy, is an early stage of diabetic retinopathy. In this stage, tiny blood vessels within the retina leak blood or fluid. The leaking fluid causes the retina to swell or to form deposits called exudates (seen in picture below).

Many people with diabetes have mild NPDR, which usually does not affect their vision. When vision is affected, it is the result of macular edema or macular ischemia, or both.

If you have diabetes, early detection of diabetic retinopathy is the best protection against loss of vision. You can significantly lower your risk of vision loss by maintaining strict control of your blood glucose and visiting your ophthalmologist regularly. People with diabetes should schedule examinations with dilation at least once a year. Pregnant women with diabetes should schedule an appointment in their first trimester, because retinopathy can progress quickly during pregnancy. More frequent medical eye examinations may be necessary after a diagnosis of diabetic retinopathy is made.

Background Diabetic Retinopathy:     

(BDR or NPDR) with exudates and bleeding

Proliferative Diabetic Retinopathy

Proliferative diabetic retinopathy (PDR) is a complication of diabetes caused by changes in the blood vessels of the eye. If you have diabetes, your body does not use and store sugar properly. High blood sugar levels create changes in the veins, arteries, and capillaries that carry blood throughout the body. This includes the tiny blood vessels in the retina, the light-sensitive nerve layer that lines the back of the eye.

In PDR, the retinal blood vessels are so damaged they close off. In response, the retina grows new, fragile blood vessels or develops neovascularization or NV (neo, for new and vascularization, for vessels). Unfortunately, these new blood vessels are abnormal and grow on the surface of the retina, so they do not resupply the retina with blood.

Often, these new blood vessels bleed and cause a vitreous hemorrhage (VH). Blood in the vitreous, the clear gel-like substance that fills the inside of the eye, blocks light rays from reaching the retina. A small amount of blood (one drop even) will cause dark floaters, while a large hemorrhage might block all vision, leaving only light and dark perception.

The new blood vessels or neovascularization can also cause scar tissue to grow. The scar tissue shrinks, wrinkling and pulling on the retina and distorting vision. If the pulling is severe, the macula may detach from its normal position and cause vision loss from a retinal detachment.

Laser surgery may be used to shrink the abnormal blood vessels and reduce the risk of bleeding.  Other, newer medicines may also help shrink the abnormal blood vessels.  The body will usually absorb blood from a vitreous hemorrhage, but this can take days, months, or even years. If the vitreous hemorrhage does not clear within a reasonable time, or if a retinal detachment is detected, an operation called a vitrectomy can be performed. During a vitrectomy, the retina surgeon removes the hemorrhage and any scar tissue that has developed, and performs laser treatment to prevent new abnormal vessel growth.

People with PDR sometimes have no symptoms until it is too late to treat them. The retina may be badly injured before there is any change in vision. There is considerable evidence to suggest that rigorous control of blood sugars decreases the chance of developing serious proliferative diabetic retinopathy.

Because PDR often has no symptoms until the vision is lost, if you have any form of diabetes you should have your eyes examined at least yearly by Dr. Haas.

Proliferative Diabetic Retinopathy: 

(PDR of the Optic Disc seen as tiny new blood vessels)

Macular Edema

Macular edema is swelling or thickening of the macula, a small area in the center of the retina that allows us to see fine details clearly. The swelling is caused by fluid leaking from retinal blood vessels, and is the most common cause of visual loss from diabetes. Vision loss from macular edema may be mild to severe, but even in the worst cases, peripheral (side) vision continues to function. Laser treatment and anti-VEGF injections (anti vascular endothelial growth factor) can be used to help control vision loss from macular edema. 

Because the macula is surrounded by many tiny blood vessels, anything that affects blood vessels elsewhere in the body (like diabetes) can cause macular edema as well.

Retinal blood vessel obstruction, eye inflammation, and age-related macular degeneration have all been associated with macular edema. The macula may also be affected by retinal swelling following cataract extraction, although this is less common.

Treatment seeks to remedy the underlying cause of the edema. Eyedrops, injections of steroids or other, newer medicines (anti-VEGF) in or around the eye, or laser surgery can be used to treat macular edema. Recovery depends on the severity of the condition causing the edema.

Macular ischemia
occurs when small blood vessels (capillaries) close. Vision blurs because the macula no longer receives sufficient blood supply to work properly. Unfortunately, there are no effective treatments for macular ischemia.

A medical eye examination is the only way to discover any changes inside your eye. If Dr. Haas finds diabetic retinopathy, he may order color photographs of the retina or a special test called optical coherence tomography (OCT) to find out if you need treatment.

Diabetic Macular Edema: