Most times when I ask a new patient with diabetes why they are in my chair, rarely is it because they came on their own.
To me, this means that this patient may not truly know how serious diabetes can be or how it can affect their eyes.
Diabetes is the leading cause of blindness in adults 20-74 years old.
Vision loss related to diabetes will triple between 2005 and 2050, in addition to the increases in diabetes itself.
Diabetic retinopathy alone will be responsible for 12,000 to 24,000 new cases of blindness each year.
I advocate diabetes patients work with their health team to integrate medical nutrition therapy based on evidence-based recommendations as stated by Chous in Review of Optometry, which are as follows:

• A low carbohydrate/low fat, energy-restricted diet to achieve ~5 - 7% weight loss in obese patients
• 150 minutes of exercise per week
• Increased dietary fiber intake (shown to slow the progression of diabetic retinopathy in the Diabetes Control and Complications Trail (DCCT))
• Elimination of trans fat intake
• Reduction of saturated fat intake (less than 10% of total caloric intake)

Although there is no true consensus or specific recommendations in the scientific community, some nutritional supplements do biologically make sense in promoting vision and overall health.
I can not stress enough to ALWAYS consult with your doctor before starting any supplement or exercise regimen.
Here are a few examples as stated in Review of Optometry:

• Omega-3 fatty acids (Fish Oil) - Some evidence suggests that Omega-3 fatty acids may reduce cardiac arrhythmias and improve clinical depression in people with diabetes.
  Omega-3 fatty acids may also decrease the risk of dry eye by increasing the quantity and quality of tears.
  
• Xanthophyll carotenoids (AMD supplements) - There is a 67% decreased likelihood of developing diabetic retinopathy in patients with high serum levels of lutein/zeaxanthin and lycopene.
  The micro nutrients of an AREDS (Age Related Eye Disease Study) supplement may also block oxidative and nitrative stress of the retina, therefore inhibiting diabetic retinopathy.
  
• Benfotiamine - A lipophilic analog of vitamin B1 has shown promise to completely prevent diabetic retinopathy in animal models of diabetes, but is still under investigation in humans.
  
• Pycnogenol - A standardized extract of French maritime pine bark and is composed of procyanidins and phenolic acids that seem to have anti-inflammatory properties which may retard capillary leakage in diabetic retinopathy.
  
• Taurine - An amino acid that supports glial function within the retina and therefore minimizes diabetic retinopathy.
  
• Vitamin D, Alpha lipoic acid, and Chromium also may play beneficial roles in diabetes, but not directly to the ocular complications.
  

Finally a simple, but important recommendation I make to all my diabetic patients is to use some type of artificial tear supplement or ocular lubricant.
The nerves that control the lacrimal glands of diabetic patients are often affected by autonomic neuropathy, causing insufficient tear production.
The best way to defend against this process is strict blood sugar control.
High blood glucose not only leads to the neuropathy, but it will disrupt the normal chemical composition of tears, exacerbating the dry eye.
People with diabetes should expect a few things when you visit your eye care provider:

• Know your hemoglobin A1c number as it determines your risk of related ocular complications.
  
• Expect to discuss lifestyle choices including what and how much you eat.
  
• Eating certain foods like white bread, pasta and potatoes are linked to eye disease in diabetics.
  
• Increasing intake of fiber, fruits, vegetables, and fish may prevent eye disease.
  
• Nutritional supplementation may also be recommended.
  

Finally, we will say it over and over again until you are sick of us, STRICT BLOOD SUGAR CONTROL is your best defense against diabetic complications, including vision complications.