Understanding and Treating Diabetic Retinopathy

Understanding how diabetic retinopathy develops...

The retina is an extension of brain matter, consisting of one and a half million nerve cells. Retinal ganglion nerve cells, both in the brain and in the retina, have a huge demand for oxygen and nutrients.

• Anything that interferes with the blood flow to the retina or the brain, even for a few minutes, can cause permanent damage. This is the mechanism of a stroke.
• When diabetes is not well controlled and blood sugars run consistently high, elevated insulin level damages retinal vessels and the blood circulation suffers.
• When we look at the retina of an uncontrolled diabetic we are likely to see leakages of serum, called exudates, and small out-pouchings of the small arteries called microaneurysms. This is called pre-proliferative retinopathy.
• Eventually we begin to see small "dot-blot" hemorrhages and even fluid build-up in the central retina, the macula (macular edema).
• Finally we see growth of new, defective blood vessels (neovascularization) due to the starvation of the tissue for oxygen and subsequent release of VEGF (vascular endothelial growth factor). This is the dangerous stage (proliferative retinopathy) in which scar tissue may form and contract, tearing the retina and producing an untreatable retinal detachment and blindness.

Normal Retina	Diabetic retina with bleeding and scarring

If you have diabetes it's absolutely critical that you see your eye doctor at least yearly.

It's always disturbing to see a retina that looks like this, and even more so when I think that the same process is undoubtedly occurring in the brain, the kidneys, the liver and all the nerves throughout the body.

Treatment of Pre-Proliferative Diabetic Retinopathy

There is good news on the treatment of the milder form of diabetic retinopathy, pre-proliferative retinopathy.

The good news is that if you treat your general diabetes with good diet (see the recommendations in Nutrition Principles), lose weight, exercise and don't smoke; both your general diabetes and your diabetic retinopathy will usually get better.

• I've seen diabetic patients return after a year and have better looking retinas than the year before, especially after significant weight loss.
• I highly recommend diabetic patients buy and read "The China Study" by Campbell (See Nutrition Study).
• One of the best ways to monitor your progress is to be aware of your A1C test. Your diabetic doctor will do this test on a regular basis and it's much better at telling you about your progress than your blood sugar.
• A1C measures the amount of blood sugar that attaches to your red blood cells. Since these cells live about three months the test gives us a good measure of your AVERAGE blood sugar over the three-month period.
• This is more important than testing blood sugar, which only tells us what the number is right now and doesn't consider the ups and downs over time.
• Know your A1C and tell it to your eye doctor at each visit.

Treatment of Proliferative Retinopathy

All of the above recommendations for pre-proliferative retinopathy apply to proliferative retinopathy. However, due to the more serious nature of proliferative disease, there are more serious treatments.

• Proliferative retinopathy gets its name from the growth of new and defective blood vessels on the retina and sometimes on the optic nerve or iris.
• Proliferative disease is the body's urgent cry for oxygen and nutrition. The release of VEGF (vascular endothelial growth factor) occurs because the retina is slowly suffocating.
• Due to the poor quality of the diabetic arteries and veins, there is no way to provide enough of an increase to stop the progression of the disease.
• Reducing the demand for oxygen is the only remaining treatment.
• This requires the use of an argon laser to "spot treat" the outer retina, effectively killing peripheral retina in a grid-pattern called pan-retinal photocoagulation (PRP).
• This does reduce peripheral vision but may be the only way to save the retina.
• Under some conditions injections of anti-VEGF drugs like Avastin or Lucentis are also used to reduce neovascularization. These treatments often must be repeated.

Proliferative retinopathy is a sight-threatening disease and should be managed by a retinal specialist.

Recommendations

If you have risk factors for diabetes but not the actual disease, eat well (See Nutrition Principles), exercise, keep your weight down and don't smoke. Prevention is always far better than the best treatment.

If you have diabetes, the same advice applies. In addition, read "The China Study" and see your eye doctor every year.

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