Complications from elevated blood sugar can damage retinas and threaten vision.
Nancy* knew as far back as high school that she wanted to work in the medical field, specifically as a nurse. Ultimately, Nancy spent more than 30 years as a registered nurse specializing in critical care.
“I managed a couple of intensive care units and served as a site administrator, but mostly I did critical care,” recounts Nancy, 62. “The thing I liked best about it was dealing with the families. I worked for a trauma critical care unit in Houston. Trauma is a little different than the other specialties because the families are very involved. I really enjoyed that aspect of the job.”
A Detroit native, Nancy lived in Houston for 20 years before moving to Florida and retiring four years ago. Sadly, her favorite retirement activities — reading, cooking and working on the computer — were interrupted by an eye issue.
“About a year and a half ago, I noticed my vision was not nearly as good as it used to be,” Nancy laments. “My vision was blurry, and it was getting harder and harder to read, which I do a lot. I bought readers, but my vision was still blurry. My driver’s license was coming up for renewal, so I figured I’d get my eyes checked.
“I made an appointment with my eye doctor, and she noticed I had cataracts (a clouding of the lens). She referred me to a physician that specializes in cataracts. That doctor took pictures of my eyes and told me I had macular edema, a complication of diabetic retinopathy.”
Diabetic retinopathy is a chronic disease caused by diabetes in which high blood sugar damages the blood vessels in the retina, the light-sensitive layer of nerve tissue lining the back of the eye. Macular edema is a buildup of fluid in the center of the retina, or macula.
“The doctor said he couldn’t do surgery to remove my cataracts as long as I had the macular edema,” Nancy remembers. “He referred me to Dr. Silva at Florida Retina Institute.”
Ruwan A. Silva, MD, MPhil, is a fellowship-trained retina specialist. During Nancy’s first appointment, Dr. Silva performed several tests and determined that macular edema secondary to diabetic retinopathy was the most likely cause of her vision loss.
Retinal Alterations
With diabetic retinopathy, multiple alterations occur in the retina due to damage from diabetes, Dr. Silva informs.
“When blood sugar levels are elevated for a prolonged period of time, typically years, changes begin to occur in the back of the eye,” the retina specialist details. “These changes take different forms, but the common denominator is damage to the lining of the small blood vessels supplying the retina. Exactly how this happens is still being investigated.”
As this damage occurs, the vessels lose their ability to carry blood. Blood and fluid spill out of the vessels, causing swelling in different areas of the retina. In addition, the retinal tissues experience a lack of blood flow and, therefore, a lack of oxygen, a condition called ischemia.
“The eyes are very metabolically active, so they are extremely dependent on the oxygen and nutrients supplied by the blood,” Dr. Silva asserts. “Patients usually become symptomatic once ischemia occurs in the retina.”
In the early stages of diabetic retinopathy, there are typically no symptoms. As the condition progresses and ischemia occurs, patients may notice blurry or cloudy vision. They may see dark spots, or floaters, or have empty areas in their vision.
During a dilated eye exam, a retina specialist can usually detect the changes associated with diabetic retinopathy before the patient loses vision. With the pupils enlarged, physicians can get a clear look at the back of the eye.
“To fine-tune our diagnosis, we may use certain types of imaging,” Dr. Silva explains. “Fluorescein angiography involves injecting a dye into the patient’s arm and taking photographs of the blood as it flows through the retinal blood vessels. Optical coherence tomography, or OCT, uses infrared light to highlight areas of thickening in the back of the eye.”
Treatment for early stage diabetic retinopathy often involves regular monitoring for progression along with counseling on diabetes management, specifically the need for tight control of blood sugar.
“If patients become symptomatic and have significant swelling in the retina or macula, we recommend a series of medication injections into the eyes,” Dr. Silva states. “The medication stabilizes the blood vessels and stops them from leaking.”
“The injection itself takes just moments and doesn’t hurt at all.” – Nancy
The medications target vascular endothelial growth factor, a protein that encourages the growth of blood vessels. Florida Retina Institute uses three FDA-approved anti-VEGF medications: bevacizumab (brand name AVASTIN®), ranibizumab (LUCENTIS®) and aflibercept (EYLEA®). Dr. Silva is treating Nancy’s diabetic retinopathy with EYLEA.
“We can also use lasers to treat diabetic retinopathy. Sometimes, we use a very gentle laser to ease the swelling and allow the body to reabsorb the fluid. If the retinopathy is advanced, we use a much more aggressive laser to stabilize the blood vessels.
“When diabetic retinopathy is very advanced, injections and lasers may not be entirely effective, and we may consider surgery. That involves entering the eye and surgically repairing the damage to the retina.”
“Painless Injections”
Nancy’s first visit to Florida Retina Institute was in mid-December.
“Dr. Silva gave me an injection in my right eye that day,” she recalls. “A week later he gave me an injection in my left eye to see how I’d tolerate it. During a subsequent visit, he gave me injections in both eyes.
“I was really nervous the first time I received an injection, but it wasn’t bad. They used drops to numb my eye and then they gave me a little injection to numb it even further. The injection itself takes just moments and doesn’t hurt at all.”
Since her treatment began, Nancy has noticed an improvement in her vision. She says it’s still a little blurry, but she attributes that to her cataracts. She hopes to soon have surgery to remove the cataracts.
“Overall, my eyes are better,” she enthuses. “They aren’t as tired at the end of the day, and I don’t have to concentrate as much to read. I can read more without glasses than I could before, and seeing the computer has gotten easier. There’s been an improvement, and I expect even more improvement once I have cataract surgery.
“I really like Dr. Silva. He’s very knowledgeable, kind and compassionate. He takes time to explain things to me, and his staff is great. They do their best to make my treatment a painless process.”
