Diabetic retinopathy is the number one cause of vision loss in those who are 25 to 74 years old. Risk factors include diabetes duration, poorly controlled glucose, smoking, high blood pressure, kidney disease, pregnancy and high cholesterol.
What is diabetic macula edema, also referred to as DME? This is swelling, due to extracellular fluid accumulating in the macula. The macula is a yellowish oval spot in the central portion of the retina — in the inner segment of the back of the eye — and it is sensitive to light.
The macula is the region with greatest visual acuity. When fluid builds up from blood vessels leaking, there is potential for vision loss.
The longer you have diabetes, the higher your risk for DME. DME is traditionally treated with lasers, but intravitreal (intraocular — within the eye) injections of a medication known as ranibizumab (Lucentis) may be as effective.
Unfortunately, many patients are diagnosed with DME after it has already caused vision loss. If not treated within the first year, patients can experience permanent vision loss.
In a study using NHANES data from 2005-2008, among patients with DME, only 45 percent were told by a physician that diabetes had affected their eyes. Approximately 46 percent of patients reported that they had not been to a diabetic nurse educator, nutritionist or dietitian in more than a year — or never.
The problem is that the symptoms of vision loss don’t necessarily occur until the disorder’s later stages. The authors note that many patients are unaware of the association between vision loss and diabetes.
Treatment options: lasers and injections
There seems to be a potential paradigm shift in DME treatment. Traditionally, patients had been treated with lasers. The results from a randomized controlled trial, the gold standard of studies, showed that intravitreal (delivery directly into the eye) injections with ranibizumab, whether given prompt laser treatments or treatments delayed for at least 24 weeks, were equally effective in treating DME.
Increased risk with diabetes drugs
You would think that drugs to treat type 2 diabetes would prevent DME from occurring as well. However, in the THIN trial, a retrospective study, a class of diabetes drugs, thiazolidinediones, which includes Avandia and Actos, actually increased the occurrence of DME.
Those receiving these drugs had a 1.3 percent incidence of DME at year one, whereas those who did not had a 0.2 percent incidence. This incidence was persistent through 10 years of follow-up.
To make matters worse, those who received both thiazolidinediones and insulin had an even greater incidence of DME. There were 103,000 diabetes patients reviewed. It was unclear whether the drugs or the severity of the diabetes itself may have caused these findings.
This is in contrast to a previous ACCORD eye substudy, which did not show an association between thiazolidinediones and DME. Thus, we need a prospective trial to sort out these results.
The risk of diabetic retinopathy progression was significantly lower with intensive blood sugar control using medications, one of the few positive highlights of the ACCORD trial.
Medication-induced intensive blood sugar control also resulted in increased mortality and no significant change in cardiovascular events. However, an inference can be made: a nutrient-dense, plant-based diet that intensively controls blood sugar is likely to decrease the risk of diabetic retinopathy complications.
The best way to avoid diabetic retinopathy is to prevent diabetes. Barring that, it’s to have sugars well-controlled. If you or someone you know has diabetes, it is imperative that they get a yearly eye exam from an ophthalmologist so that diabetic retinopathy is detected as early as possible, before permanent vision loss occurs.
It is especially important for those diabetes patients who are taking thiazolidinediones, which include rosiglitazone (Avandia) and pioglitazone (Actos).
For further information, visit medicalcompassmd.com or consult your personal physician.