No Sugar Coating It

Diabetic retinopathy destroys vision.

Diabetes is a common disease that wreaks havoc on the body if not controlled. It develops when people have too much sugar, or glucose, in their blood. Glucose is the body’s main source of fuel for living, and it comes from the food people eat. A hormone made by the pancreas called insulin helps glucose get into the body’s cells to be used as energy.

Unfortunately, some people don’t make enough insulin, or the insulin they make doesn’t work properly. When this occurs, glucose can’t enter the cells efficiently and builds up in the bloodstream.

“Consistently high levels of glucose in the blood damages the small blood vessels throughout the body,” notes Tomas A. Moreno, MD, a board-certified, fellowship-trained retina specialist at Florida Retina Institute.

“The retina, the light-sensing organ of the eyes, is nourished by small blood vessels, and when diabetes damages those blood vessels and causes leakage and bleeding inside the retina, it’s a condition called diabetic retinopathy.”

There are two main types of diabetic retinopathy: non-proliferative and proliferative. In non-proliferative diabetic retinopathy, the small blood vessels in the retina are weakened and begin to bulge and leak.

This leakage can result in swelling of the retina and macula, which is the portion of the retina responsible for the sharp, central vision needed to perform tasks such as reading, driving and distinguishing faces, and ultimately lead to vision loss.

“With proliferative diabetic retinopathy, the blood vessels are extensively damaged and actually get blocked off, which deprives the retina of oxygen,” Dr. Moreno explains. “The retina needs oxygen, however, so it creates abnormal blood vessels through a process known as neovascularization.

“But the blood vessels created through neovascularization are unstable and can bleed into the vitreous, the jelly-like material in the center of the eye. That’s a vitreous hemorrhage, and it can result in scarring of the retina and a retinal detachment.

“A retinal detachment occurs when scar tissue on the retina pulls it away from the back of the eye. A retinal detachment is a serious complication and an emergency situation to save vision.”

Most people with diabetes don’t notice any symptoms with mild to moderate cases of diabetic retinopathy, Dr. Moreno states. But symptoms often begin to appear as the disease progresses.

“In the moderate stages of diabetic retinopathy, people may experience blurred vision throughout the day as their blood glucose rises and falls,” the doctor observes. “In the later stages, they may also notice flashing lights, eye floaters or decreased vision that doesn’t improve with eye drops or blinking the eyes.

“As the disease progresses further, people may experience distortion in their vision, with straight lines appearing curvy. In severe cases, they may present with acute vision loss. At that point, they may be able to see only motion or only light, so it’s critically important to catch diabetic retinopathy in its early stages.”

The Gold Standard

Retina specialists such as Dr. Moreno use a series of tests to diagnose diabetic retinopathy. These tests give eye doctors specific information about the disease that helps them determine the appropriate treatment.

“The gold standard for detecting diabetic retinopathy is the dilated fundus exam,” Dr. Moreno asserts. “To perform this exam, a qualified eye doctor places drops in the patient’s eyes to dilate the pupils. The doctor then looks inside the patient’s eyes for any evidence of retinal swelling, leaking blood vessels or neovascularization.

“We can also use a test called optical coherence tomography, or OCT, which is like a high-definition ultrasound, but instead of using sound to produce the images, OCT uses light. OCT enables us to measure the thickness of the retina to determine if there’s any swelling present.”

Fluorescein angiography is a test to examine blood flow within the retina to identify blood vessel blockages and leakages. During this test, a dye called fluorescein is injected into a vein in the patient’s arm. The dye travels through the bloodstream to the eyes, where pictures are taken of the blood flow through the retina.

Armed with information from the patient’s history of symptoms, as well as the results of the diagnostic tests, the retina specialist develops a tailored treatment plan. Over time, treatments for diabetic retinopathy have advanced and now provide improved results.

“In the past, if a patient with diabetic retinopathy had minor swelling of the retina, we used a focal laser to repair the individual leaking blood vessels,” Dr. Moreno describes. “That reduced progression of the condition by one-third. It was something, but it wasn’t great.

“Yearly examinations by a retina specialist or comprehensive eye doctor have reduced blindness from diabetic retinopathy by more than ninety-five percent in some studies.” – Dr. Moreno

“Now, we can actually inject a medicine called anti-vascular endothelial growth factor, or anti-VEGF, into the patient’s eye. VEGF is a substance that encourages the growth of new blood vessels. Discouraging that growth with this medicine prevents leakage and reduces swelling of the retina. Anti-VEGF injections are the mainstay treatment for non-proliferative diabetic retinopathy.”

The most appropriate treatment for proliferative diabetic retinopathy depends on its severity. If there’s extensive blood vessel blockage, eye doctors typically laser the periphery of the retina. This area is most deprived of oxygen and most susceptible to the formation of new, unstable blood vessels. By lasering this area, doctors decrease its need for new blood vessels and stabilize the disease.

“If there’s significant bleeding inside the eye that doesn’t clear up on its own, or if there’s significant scarring, we typically perform a vitrectomy,” Dr. Moreno informs. “During vitrectomy, we remove the jelly-like vitreous, peel back the scar tissue and apply a laser to the retina. This is an outpatient surgery, but it’s still surgery. It’s done as a last resort.”

Photos courtesy of Florida Retina Institute.

Tomas A. Moreno, MD

These treatments are not a cure for diabetic retinopathy, Dr. Moreno stresses, but they may halt or slow the progression of symptoms. People with diabetic retinopathy must continue to monitor their symptoms and report any changes in their vision to their eye doctors right away.

Vision Preservation

Diabetes is a long-term, chronic illness that must be controlled, and patients with diabetes must always be mindful of the development of diabetic retinopathy. That’s why routine check-ups by a qualified eye doctor are so important.

“Yearly examinations by a retina specialist or comprehensive eye doctor have reduced blindness from diabetic retinopathy by more than ninety-five percent in some studies,” Dr. Moreno reports. “However, compliance with yearly eye exams was less than fifty percent in those studies.

“Many people with diabetes don’t know they have eye problems from diabetic retinopathy in its early stages, so it’s critically important for us to see these patients and examine their retinas regularly.

“Lucky for them, we can actually see the retina and pick up on any changes before the patients experience visual consequences. We can then tailor our follow-ups to intervene when changes are detected.”

Prevention is the biggest factor in saving vision, Dr. Moreno emphasizes. “People with diabetes must keep their blood glucose under control and see their eye doctors at least yearly to stay ahead of diabetic retinopathy.”

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    • Florida Retina Institute

      Founded by James A. Staman, MD in 1979, Florida Retina Institute has 19 locations throughout Central Florida, North Florida, and Southeast Georgia. They have proudly delivered Excellence in Vitreo-Retinal Diseases and Surgery for 40 years. T... Read More

    • Tomas A. Moreno, MD

      Tomas A. Moreno, MD, is board certified by the American Board of Ophthalmology. He earned a bachelor of science degree from Duke University and his Doctor of Medicine degree from Duke University School of Medicine. Dr. Moreno completed an inter... Read More