Diabetic Retinopathy Stages

Diabetic retinopathy is a common complication of type 1 and type 2 diabetes.  It starts with damage to the blood vessels in the retina of the eye (which is the “seeing” part of the eye) and ends with neovascularization, which is the formation of extra capillaries (small blood vessels) that leads to blindness.

Diabetic retinopathy is more common among diabetics who do not keep their blood sugars under control. The elevated glucose level changes the lining of the blood vessels of the eye so that the blood vessels become damaged, starting the process of the disease.

When the blood vessels of the eye become damaged, they begin to leak blood fluid.  This swells the tissues of the retina so that the vision eventually becomes blurry or cloudy.  It usually happens in both eyes at the same time.  The longer you have type 1 or type 2 diabetes and the worse your diabetic control, the greater is the chance of having diabetic retinopathy and blindness.

Symptoms of Diabetic Retinopathy

Typical symptoms of diabetic retinopathy include having difficulty with vision during the night, having a blank spot in the middle of the visual field, having blurry vision, and seeing floaters and spots when trying to see something. The greater the blood sugar levels, the more symptoms of diabetic retinopathy you will have.

Vitreous fluid from the eye can build up on the lens of the eye so that it swells.  This is worse when the blood sugars are in poor control.  The lens normally focuses and sharpens the vision so that, if you have diabetic retinopathy, you will have an inability to see things sharply.  If you can get the blood sugars under control, the swelling of the lens improves so that you can have an improvement in your vision.

There are very few or no symptoms in the earliest stages of diabetic retinopathy.  Because there are no symptoms, you need to be screened for the disease every year after you have been diagnosed with diabetes.  A dilated eye examination is recommended for every diabetic by the American Optometric Association.  If the condition can be diagnosed and prevented early enough, the main complication of blindness can be stopped.

Slowing the Development of Diabetic Retinopathy

There are things you can do to slow the development of the disease and prevent blindness.  These include the following:

• Staying away from alcohol
• Quitting smoking
• Keeping the blood pressure in good control
• Engaging in regular exercise
• Taking the prescription medications your doctor has recommended
• Eating a healthy, low sugar diet

Stages of Diabetic Retinopathy

The early stage of diabetic retinopathy is also known as “non-proliferative diabetic retinopathy”.  There will be no symptoms but the blood vessels in the retina of the eye have already become weak so that small micro-aneurysms occur in various spots along the blood vessels.

The more advanced stage of diabetic retinopathy is called “proliferative diabetic retinopathy”. When you reach this stage, tiny capillaries begin to grow from the retinal area and into the vitreous, which is the gelatinous fluid that makes up the inside of the globe of the eye.  These new capillaries are very delicate and can cause leakage of blood into the vitreous.  Vision can be impaired when this happens.

The damaged blood vessels are the main reason why blindness occurs in diabetic retinopathy. The damaged blood vessels decrease vision by doing the following:

• Leaking fluid into the macular part of the eye. The macula is the part of the retina that allows for clear vision in the center portion of the visual field. It is also the part of the eye that allows people to see color vision and the details in the vision.
• New blood vessels form as a result of low oxygen concentration in the retina. These new blood vessels, called capillaries, are extremely delicate and leak blood into the back portion of the eye.  The retina cannot be seen through the blood and so you can become blind.

Risk Factors for Diabetic Retinopathy

There are several risk factors for diabetic retinopathy, including the following:

• Women who are pregnant have a higher than normal chance of developing both diabetes and diabetic neuropathy.  Women who have gestational diabetes have a greater chance of having type 2 diabetes later in life, which can cause diabetic retinopathy.
• You can get diabetic retinopathy with both type 1 and type 2 diabetes.  The worse your blood sugar levels and the longer you have the disease, the greater is your chances of developing diabetic retinopathy.
• If you have other medical illnesses, such as high cholesterol levels or hypertension, you have a greater chance of developing diabetic retinopathy.
• People who are African American or Hispanic have a greater than average chance of developing diabetic retinopathy when compared to people of other ethnicities.

Pathophysiology of Diabetic Retinopathy

The first thing that happens in diabetic neuropathy is edema (swelling) of the macula.  This is why the person with non-proliferative diabetic retinopathy has poor vision.  While macular edema is more common among those with non-proliferative disease, it can also be seen in proliferative diabetic retinopathy.

As the disease worsens, the capillaries of the retina will close off, leading to a lack of oxygenation to the eye.  Death ensues from lack of oxygen and the nerves in the eye are damaged.  This leads to the formation of “cotton-wool” spots in the retina, which can affect vision.

When the lack of blood flow to the eye becomes even worse, the eye tries to compensate by attempting to make new capillaries to send oxygen to the retina. This is called neovascularization.  There are factors released as a result of the poor blood flow that triggers the formation of these new capillaries. The capillaries interfere with vision, making blindness an increasing possibility.

Diagnosing Diabetic Retinopathy

There is no blood test to see if you have diabetic retinopathy.  Instead, the disease is detected by having a complete eye exam in which the pupils are dilated so that the ophthalmologist can see the retina.  The changes of diabetic retinopathy can be seen with the naked eye during this type of examination.

The ophthalmologist will ask you about your medical history, including any problems with vision you might have, any history of diabetes you have, and other medical conditions you might have that would interfere with normal vision.

The ophthalmologist will also check your eyes for refractive errors that might mean you need glasses and will check your visual acuity to see if your central vision has been damaged by diabetic retinopathy.  The pressure of the eye will be checked for glaucoma and the structures of the eye will be checked to see if you have any signs of eye diseases.

In some cases, the doctor will do a retinal photograph to see what the retina looks like now in order to see if there have been any changes in the future.  A fluorescein angiography may be performed to see if there has been a growth of capillaries on the retina.

Treatment of Diabetic Retinopathy

The treatment of the condition depends on the stage of the person’s retinopathy.  Laser surgery is sometimes done to burn off and seal the leaking capillaries and to prevent new capillaries from forming.  Medications may be injected into the eye that decrease the level of inflammation in the eye and to stop the formation of new capillaries.  In some cases of severe disease, part of the damaged vitreous is removed so that vision can be improved. If the retina detaches, surgery can be done to reattach the retina.

References:

• Diabetic retinopathy. http://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/diabetic-retinopathy?sso=y. Accessed 5/22/16.
• Diabetic retinopathy. http://emedicine.medscape.com/article/1225122-overview#a3. Accessed 5/22/16.