Diabetic Retinopathy: Have You Lost Vision from Diabetic Retinopathy?

Diabetes Unlikely to Cause Blindness
October 14, 2009
Addendum to "The Stages of Diabetic Retinopathy"
October 16, 2009
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Diabetic Retinopathy: Have You Lost Vision from Diabetic Retinopathy?

There are 4 stages of diabetic retinopathy. Each stage is based upon the appearance of the retinas at the time of examination and are not based upon a patient’s symptoms, including vision.  Many people with early diabetic retinopathy have no symptoms.  Therefore, regardless of whether you are experiencing symptoms, it is imperative that if you have diabetes you schedule regular eye exams.  If you are symptomatic your symptoms may include blindness, blurred vision, floaters or missing areas in your vision.


When a patient with diabetes comes to my office I am looking to see if the diabetes has caused damage to the blood vessels of the retina, the light sensitive inner layer of the eye.  Generally, there are two main types of retinopathy:  non-proliferative retinopathy and proliferative retinopathy.  Within those two main types of retinopathy there are four stages.   They are mild non-proliferative diabetic retinopathy, moderate non-proliferative diabetic retinopathy, severe non-proliferative diabetic retinopathy, and proliferative diabetic retinopat

Retinal Examination:  The Relative Stages of Diabetic Retinopathy:

0.  No Disease – retina is completely normal, no signs of diabetic retinopathy.

STAGE 1: Mild non-proliferative diabetic retinopathy.

The earliest signs of diabetic retinopathy are seen.  There may be abnormalities in the blood vessels called microaneurysms.  The microaneurysms can leak.   Blood flow to the retina is usually normal.  There are no signs of ischemia (insufficient blood supply to the retina).  At this point there is no chance of blindness.

STAGE 2: Moderate non-proliferative diabetic retinopathy.

Microaneurysms are present.  There are now signs of retinal ischemia.  These findings are called soft-exudates.  Retinal ischemia, itself can cause loss of vision, as can swelling from microaneurysms.  Again, there is no chance of blindness with this stage.

STAGE 3: Severe non-proliferative diabetic retinopathy

Microaneurysms, and soft exudates abound.  There are more signs of progressive retinal ischemia.  The chance of vision loss from ischemia is higher.  The chance of the disease advancing to proliferative diabetic retinopathy is increasing.  There is no chance of blindness.

STAGE 4: Proliferative diabetic retinopathy (PDR)

Abnormal blood vessels, called neovascularization, are now present and are the hallmark of this stage of the disease.  These abnormal blood vessels can grow along the surface of the retina and cause a retinal detachment.  This is the mechanism by which patients with diabetic retinopathy can go blind.  Laser surgery (i.e. panretinal photocoagulation, aka PRP) may be needed to stabilize the disease.  In cases where a retinal detachment has started, intraocular surgery, called vitrectomy, may be indicated.


a)  Macular edema can be present in any 4 of the stages.  It is usually treated with laser treatment, but steroids or anti-VEGF medications may be useful, too.  Macular edema, also called diabetic macular edema (DME) or clinically significant macular edema (CSME) is not necessary for staging.

b)  The first 3 stages have the terms “non-proliferative” associated and, therefore, do not carry the possibility of blindness.  “Proliferative” disease is noted by the presence of neovascularization, which can cause retinal detachment and, thus, blindness.

c)  There is nothing to do for the “non-proliferative” phases of the disease.  Treatment is only needed for macular edema (any stage) and proliferative diabetic retinopathy (PDR).

d)  The stages of diabetic retinopathy are not necessary sequential, that is, a patient may have no retinopathy and then 6 months later, might show signs of having proliferative diabetic retinopathy.  Diabetic retinopathy may skip stages.

My job is simple. When a patient with diabetic retinopathy comes for examination; I am only looking for two things; signs of macular edema and proliferative disease.  It really is pretty straight forward.  If neither is found, then no treatment is needed.


Randall V. Wong, M.D.
Ophthalmologist, Retina Specialist

  • Joanne October 15, 2009 at 1:51 pm

    Is it possible that between visits – say of six months, a patient can go from one stage to another? Or can become worsened within the stage they are in, without knowing it? What would be warning signs other than we can’t see as well as we used to?

    • Randall V. Wong, M.D. October 15, 2009 at 3:45 pm

      Actually, I forgot that aspect in today’s post. I forgot to mention that a patient can go from one stage to another, or skip stages.



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