Diabetic Eye Disease

It is very important to know how diabetes can affect eye sight. If untreated, diabetic eye disease can lead to loss of or even blindness. In fact, diabetes is the most common cause of blindness in people between 25 and 65 years of age.
Detecting diabetic eye disease in its earliest, most treatable stage and following through with proper treatment can prevent loss of sight most of the time. In addition, new medical and surgical treatments can now restore sight to many diabetics who already have problems with their eyes. To help you understand how diabetes can affect your eyes or the eyes of someone you love, reflect back on our earlier explanation of how the eye works.

What does diabetes do to the Retina?

As you know, diabetes is a disease in which your body has trouble using sugar, the main source of energy. The trouble involves insulin, a hormone produced by a gland called the pancreas. In diabetics, insulin is either not produced in enough quantity, is not released into the blood at the right time, or is not able to do the job it's supposed to do.
Over a period of years, diabetes damages the small blood vessels throughout your body, especially those in the kidneys, feet, and eyes. When the small blood vessels become diseased, they are not able to properly newer action these tissues. When the small blood vessels of the rest and are damaged by diabetes, we call it diabetic retinopathy ("opathy" means "disease of")
Normal retina blood vessels are water tight and do not leak. When diabetes first weakens the small blood vessels in the retina, they begin to leak fluid and blood, causing the retinal tissue to swell and become thickened. When the retina swells and thickens beyond a certain point, it can't work normally, and eyesight starts to blur. We call this stage of diabetic eye disease background retinopathy.

How is background diabetic retinopathy detected?

When swelling first begins it is usually very mild and may not cause blurred eyesight. The only way retinopathy can be detected at this early stage is by a retinal examination.
The best time to treat diabetes is during this early stage, before your eyesight becomes blurred. When sight is good, diabetics may not think they need to see their eye doctor - but this is the best time. Unfortunately, once blurred sight developed, diabetic retinopathy may have already reached an advance stage and treatment may be less effective.
When your eye doctor detects background retinopathy, he or she may do a special test called a fluorescein angiogram to get an exact picture of the small blood vessels in the retina. This test will show which blood vessels are leaking fluid. Once the eye doctor has this information, he or she may recommend laser treatment.

What is Laser treatment?

The laser is a special, highly focused light beam. When a person has background diabetic retinopathy, a type of laser treatment called Focal Laser Treatment is used to stop the fluid and blood from leaking into the retina. During the treatment, the leaking vessels are sealed with the laser- somewhat like spot welding a leaking water pipe.
Focal laser treatment background retinopathy is usually painless and can be performed in the doctor's office or an outpatient clinic.

What happens after laser treatment?

With focal laser treatment, we hope to stop and sometimes reverse the leaking and swelling process. However, since the diabetes is still present, follow-up visits to your eye doctor are necessary to detect new leaking blood vessels which may occur in the future.

How else can diabetes cause retina problems?

In some diabetics, the retinal blood vessels become more severely damaged and eventually clogged. When this happens, blood stops flowing to the retina. To try makeup for this, the retina sprouts new blood vessels. This process is called neovascularization; unfortunately, these new vessels cannot feed the retina- they only cause more problems.
When new blood vessels begin to grow, or proliferate, we say that proliferative retinopathy has begun. This is a more advanced stage of diabetic retinopathy.

How can these new blood vessels damage eyesight?

The new blood vessels are very fragile and bleed easily. When they do, they can fill the center of the eye with blood. If there is even a little bleeding, your sight becomes cloudy. You may also notice specs, strings, or showers of dots in your sight if a lot of bleeding occurs, your sight will suddenly become very blurred. It is very important to understand that the new vessels don't affect your sight until they start bleeding. You can develop this more severe stage of proliferative retinopathy without noticing any change in sight.

How can diabetics know if they have proliferative retinopathy?

Only a thorough retinal exam can detect proliferative retinopathy before any bleeding occurs. Early diagnosis and treatment of proliferative retinopathy is very important because the more advanced the retinopathy gets before it is treated, the harder it is to stop. This is why you must visit your eye doctor regularly. Early detection, before sight changes, and early treatment are the most important steps in preserving a diabetic patient's sight.

How is proliferative retinopathy treated?

A different type of laser treatment is used for proliferative retinopathy. It is called peripheral scatter laser treatment or Pan-Retinal Photocoagulation (PRP). (Remember that Focal Laser Treatment was used to seal the leaking blood vessels in background retinopathy) In order to stop the new blood vessels from growing, large areas of the retina are treated with the laser. Several treatments are usually necessary. Like focal laser treatment, Pan-Retinal Photocoagulation can be performed in the doctor's office or an outpatient clinic.

Do laser treatments always work?

In most cases, bleeding into the eye clears up by itself and PRP can often prevent further leading. But this is not always the case. Sometimes, the blood does not clear up after many months and sight remains very blurred. Other times, repeated bleeding can occur and prevent further laser treatments from being performed.
When there is repeated bleeding or the blood does not clear up, a special operation called a vitrectomy is recommended. For this operation, a retinal specialist uses tiny instruments and surgical microscope to remove the blood from inside the eye. He or she can then find abnormal new vessels that are causing bleeding and destroy them with the laser during surgery.
This operation is performed in a hospital and generally requires a few days a stay. Sight may remain blurred for sometimes following surgery and then improve slowly over a period of months or years.

Can proliferative retinopathy cause more problems?

When new blood vessels grow during proliferative retinopathy, they sometimes cause scar tissue to build upon the surface of the retina. If this scar tissue is mild, or if it is stopped by laser treatment, then it has no effect on your eyesight.
However if the scar tissue becomes severe, it can pull the retina out of place. This is called a traction retinal detachment. Usually sight becomes very poor when a retinal detachment develops. Vitrectomy surgery is necessary to repair this type of retinal detachment. Very delicate instruments are used to cut the scar tissue from the retina and then lasers are used to seal the retina back in place. This operation is performed in a hospital by a retina specialist. A few days stay is usually required.