1. Keep your average blood glucose as close to normal as possible (less than 100) but at least less than 150. Study after study shows that the closer blood sugar levels are kept to normal, the less risk there is of diabetic retinopathy.
2. Keep your hemoglobin-A-1-c (HbA1c) levels less than 6.5%. For HbA1c levels under 8%, each ten percent reduction (for example, reducing HbA1c from 8% to 7.2%) cuts the risk of diabetic retinopathy progression almost in half; above an HbA1c of 8%, the risk reduction is even greater.
3. Make sure your lowest low blood sugar and your highest high blood sugar are no more than ½ your average blood sugar level. Scientific evidence shows that more damage occurs to blood vessels (in the eyes and elsewhere) when blood sugar levels fluctuate a lot; minimizing these fluctuations (in the vocabulary of statistics, lowering the standard deviation of the mean) reduces the risk of blood vessel complications even when HbA1c levels are good. So, for example, if your average blood sugar level is 140 (equivalent to an HbA1c of 6.1%), try always to keep your blood sugar levels above 70 and below 210.
4. Keep your blood pressure less than or equal to 120/80, your mean arterial pressure (MAP) less than 93 and your retinal perfusion pressure (RPP) less than 45. High blood pressure accelerates diabetic retinopathy and greatly increases the risk of most diabetes complications. MAP and RPP have been found to predict those patients most likely to develop sight-threatening retinopathy, and the values cited here will place you at much lower risk. MAP = 1/3 the difference between the upper (systolic) blood pressure number and the lower (diastolic) number added to the diastolic number (e.g. for a blood pressure of 126/81, MAP = (126-81) divided by 3 + 81 = 96). RPP = 2/3 times MAP, minus your internal eye pressure - ask your eye doctor to measure and tell you this value (e.g. for a MAP of 96 and an internal eye pressure of 15, RPP = (2/3 x 96) - 15 = 49).
5. If you use fast-acting insulin to
control your blood glucose levels, take multiple small doses rather
than 1 or 2 large doses.
Several studies show that diabetic retinopathy progresses more slowly when patients take multiple small doses rather than one or two large doses of insulin. This phenomenon may be due to less blood sugar fluctuation (as discussed in #3 above) and/or to stimulation of abnormal blood vessel growth caused by higher levels of circulating insulin.
6. Consider taking 150 mg of benfotiamine three times per day, just before each major meal. This fat-soluble form of vitamin B1 (thiamine) totally prevented the development of diabetic retinopathy in animals and is now being taken by a number of diabetes specialists who have diabetes themselves (including me). Human safety and efficacy trials are underway (see my article under 'what's new' on this web site).
7. If you snore or are obese, get tested for sleep apnea syndrome and get treated if it's diagnosed. Sleep apnea (brief stoppage of breathing while sleeping) is caused by obstruction of the airway, is highly associated with overweight and obesity, and causes snoring. It has been shown to be an independent risk factor for diabetic retinopathy (and stroke) because it reduces oxygen supply to the retina (and brain).
8. Keep your blood lipids well controlled, with LDL levels below 100, triglycerides below 150 and HDL levels above 50; also, talk to your doctor about taking 162 mg of aspirin daily. People with diabetes tend to have abnormal blood lipids which are associated with numerous eye diseases, including more severe diabetic macular edema. The statin drugs lower LDL cholesterol, whereas exercise raises HDL cholesterol; Aspirin thins the blood, thereby significantly reducing the risk of stroke.
9. Move your body on a regular basis - get a pedometer and try to walk 5-10 thousand steps every day. Exercise improves metabolism and reduces insulin resistance, the hallmark of type 2 diabetes. It is now believed that insulin resistance not only causes high blood glucose levels that damage the eye but, also, that hyperinsulinemia caused by insulin resistance accelerates proliferative diabetic retinopathy. Walking is a great activity because it can be done anywhere and at low cost, while wearing a pedometer gives positive reinforcement of physical activity and makes a 'game' of it.
10. Get a dilated eye exam every year by an optometrist or ophthalmologist knowledgeable about and interested in excellent diabetes care. Most blindness caused by diabetes can be prevented if eye complications are caught in time and treated appropriately. Dilation greatly increases the risk of early detection and appropriate treatment. It's a hassle, I know, but much less so than losing your eyesight.
As an added 'bonus,' remember that the steps advocated above will not only greatly reduce your risk of losing vision to diabetes but, also, the risk of kidney disease, nerve disease, stroke, heart attack and death. For more information, consult Dr. Chous' award-winning book: