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A Silent Complication: A Closer Look at Diabetic Retinopathy

By Jackie Young, Alexander Wolf, and Nicole Kofman

Twitter Summary: Dr. Ivan Suñer gives us a closer look at diabetic retinopathy and how to prevent this “silent” complication

The diaTribe team recently interviewed leading ophthalmologist and retinal surgeon Dr. Ivan Suñer about a common diabetes complication called diabetic retinopathy (DR). Between 40% and 45% of Americans with diabetes have some stage of diabetic retinopathy, a condition that often presents no symptoms at all until it has progressed to the point of severe loss of vision. During our conversation with Dr. Suñer, he shared valuable advice on DR screening, tips on how people can prevent DR, and a glimpse of the future of DR treatments. In addition to interviewing Dr. Suñer, we spoke with Mr. Mike Ellis, a person who was diagnosed with DR at age 63. He shared with us key takeaways from his experience.

What is diabetic retinopathy?

Diabetic retinopathy is a complication of diabetes that occurs when blood vessels in the retina of the eye are damaged or swollen, or begin to grow irregularly. DR has four stages: mild, moderate, severe, and proliferative retinopathy. At first, diabetic retinopathy may cause no symptoms. If left untreated, DR can cause severe vision loss or even blindness.

As Dr. Suñer explained, DR also typically reveals the presence of other diabetes-related complications that may be occurring elsewhere in the body. For instance, a study by the American Diabetes Association indicates that people with DR are twice as likely to develop coronary heart disease and three times as likely to suffer from fatal coronary heart disease as people with type 2 diabetes with no DR.

What causes diabetic retinopathy, and who is at risk?   

Anyone with type 1 or type 2 diabetes is at risk of developing DR, which is caused by high average blood glucose over time, typically many years. Persistently high blood sugar can lead to the damage and blockage of the tiny blood vessels in the retina. When blood supply is cut off, the eye develops new blood vessels, but these new blood vessels don’t develop properly and can easily leak, causing vision loss. Additionally, the longer a person lives with diabetes, the more likely he or she is to develop DR.

How can people prevent diabetic retinopathy?

Dr. Suñer stressed the importance of monitoring and controlling blood sugar, blood pressure, and cholesterol to prevent DR. Specifically, the American Diabetes Association (ADA) demonstrates that A1c has a direct relationship with risk of developing DR, with an A1c of <6.5 being associated with a decreased risk of DR. Regular exercise also decreases risk of DR and long-term complications. He also pointed out that limited research suggests smoking cigarettes increases one’s risk for DR.

The most urgent piece of information Dr. Suñer shared was that people with all stages of DR often have no symptoms until they are at extremely high risk for vision loss. Thus, he strongly emphasized the importance of regular DR screening with a comprehensive eye examination.

Our conversation with Mr. Mike Ellis, a person diagnosed with DR, taught us the same lesson. He hadn’t seen a doctor in years when he started losing his vision, and only when he started having trouble doing the things he loved, including fly fishing and working on cars, did he see a doctor. His physician diagnosed him with type 2 diabetes and DR at the same appointment. He had no reason to believe that he had diabetes – while a majority of people with type 2 diabetes are overweight, he had always been fit and active his entire life. Thus, the number one piece of advice he wanted to share with diaTribe readers is to see a doctor regularly and receive screening for DR.

Where and when should you receive DR screening?

Early detection of diabetic retinopathy is crucial to prevent vision loss. Patients should be screened through a dilated eye exam by an ophthalmologist or optometrist. An exam done by a primary doctor, without eye dilation, is not a substitute for a full exam done by an ophthalmologist or optometrist.

It is recommended that anyone with type 1 diabetes above the age of 10 receive an initial dilated examination within five years of the onset of diabetes. For people with type 2 diabetes, it is recommended that any newly diagnosed patients receive a dilated eye exam immediately after diagnosis, as 21% of type 2 patients have some level of DR at the time of diagnosis, as did Mr. Ellis. The recommended frequency of DR screening depends on the stage of retinopathy, and can range from once a year for very mild retinopathy, to every four to six weeks for severe DR.

The silver lining of Mr. Ellis’ diagnosis with DR and diabetes at the age of 63 was that it served as a “wakeup call” to his younger siblings. After he was diagnosed with DR, he encouraged them all to get screened for diabetes. It turned out that they all had blood sugar in the prediabetes range. This information gave them the opportunity to proactively change their lifestyles, preventing the onset of type 2 diabetes and its complications.

How is diabetic retinopathy treated?

Treatment options depend largely on the severity of DR. Mild or moderate DR may not require immediate treatment, and maintaining control of one’s blood sugar can usually slow the progression of the condition.

For people with more advanced stage DR, treatment options include:

  1. Drug Treatments
    VEGF-inhibitors, such as Lucentis and Eylea, are useful drugs for those earlier in their progression who do not yet need surgery. These drugs inhibit a protein that causes damage to blood vessels in the eye and are administered by a health care provider as a monthly eye injection. According to Dr. Suñer, as many as 40% of people with DR see significant improvements after using these drugs.
  2. Focal Laser Treatment
    For patients who do not improve after drug treatment, focal laser treatment allows doctors to shrink abnormal blood vessels through a laser procedure. According to the National Eye Institute, focal laser treatments can reduce risk of vision loss by 50%.
  3. Vitrectomy
    If blood vessels in the eye have significant bleeding, a surgical procedure called a vitrectomy may be performed, during which vitreous gel containing leaked blood is removed from the eye as well as any scar tissue. Laser treatment is also performed to help prevent recurrence of abnormal blood vessels and bleeding.

In November 2015, an NIH-funded clinical trial found that Lucentis is highly effective in treating proliferative diabetic retinopathy, compared with laser treatment. After two years of treatment, the group receiving Lucentis injections had vision improvements of about half a line on an eye chart, compared with no improvement in the laser group. Additionally, there was little change in side vision for those receiving Lucentis, while those receiving laser treatment experienced a substantial loss of side vision.

When Mr. Ellis was diagnosed with DR, he started receiving injections of the VEGF-inhibitor Lucentis as a treatment. Fortunately, and amazingly, these injections have helped him regain his vision within a year. He has regained the ability to do all the activities he loves again, including fishing and tutoring children at his local church. According to his doctor, he likely would have lost his vision completely had he not caught the symptoms when he did, and if this treatment hadn’t been available to him. Although he said it’s certainly not comfortable to get injections in his eyeballs every month, it’s a small price to pay for maintaining his vision. 

Surgical interventions like focal laser treatment and vitrectomy often slow or stop the progression of diabetic retinopathy, but they are not cures. Regular eye exams are thus necessary to continue monitoring DR.

What does the future of DR treatments look like?

Dr. Suñer gave us a glimpse into new research being done on DR treatments. These include:

  1. New Drugs
    New drugs such as fenofibrate, a drug traditionally used to lower cholesterol, are currently undergoing clinical trials.
  2. Implant Devices
    Researchers are investigating implant devices that release a drug (e.g. Lucentis) over a prolonged period of time. Instead of regular and frequent injections, the goal is that patients would need to refill the device less frequently (i.e., potentially every six or eight months).
  3. Combination Therapies
    Other researchers are investigating the effectiveness of combining multiple therapies for DR early on in the treatment plan (i.e., giving a drug therapy in combination with laser therapy at the start of treatment, rather than beginning with a drug treatment and then performing surgery later on). While this research is in its early stages, Dr. Suñer has seen promising results that this combination therapy can lead to better outcomes and fewer treatments down the road.

Our main takeaway from our conversations with Dr. Suñer and Mr. Ellis is that being screened for diabetes and diabetic retinopathy is the most important action that a person can take to prevent this complication from causing severe vision loss and blindness. Maintaining good control of one’s blood sugar by getting ample exercise and controlling one’s diet can prevent DR and reverse it in its early stages, but one can only know if they are at risk for it if they frequently visit their doctor and get their eyes checked.

Special thanks to Mallika Tamboli, Katherine Weltzien, and Lillian Ackley for their research and contribution to this piece.

Homepage image from freeimages.com (Bianca Marton)
Image from American Society of Retina Specialists