When to Refer Diabetic Patients for Retina Care
Understanding Diabetic Retinopathy
Diabetic retinopathy is a complication of diabetes that damages the blood vessels in the retina, the light-sensitive tissue lining the back of the eye. Over time, high blood sugar weakens and changes these tiny blood vessels. They may leak fluid, swell, or close off entirely. In advanced stages, abnormal new blood vessels grow on the surface of the retina.
Chronic high blood sugar injures the walls of retinal blood vessels. This triggers inflammation and the release of a protein called vascular endothelial growth factor (VEGF). VEGF signals the eye to grow fragile new blood vessels. These new vessels break easily and leak blood or fluid into the eye, which can damage vision. The process can also cause scar tissue to form, pulling on the retina and raising the risk of retinal detachment.
Diabetic retinopathy progresses through two main stages. Nonproliferative diabetic retinopathy (NPDR) is the earlier stage. It involves changes such as tiny bulges in blood vessel walls (microaneurysms), small areas of bleeding in the retina, and swelling in the blood vessels. No abnormal new vessel growth has started yet.
Proliferative diabetic retinopathy (PDR) is the more advanced stage. It occurs when the retina becomes so oxygen-deprived that the eye grows new, abnormal blood vessels. These fragile vessels can bleed into the vitreous (the gel filling the inside of the eye) and lead to serious complications including retinal detachment.
Diabetic macular edema (DME) is swelling in the macula, the central part of the retina responsible for sharp, detailed vision. DME can occur at any stage of diabetic retinopathy. When fluid leaks into the macula, it causes blurred or distorted central vision. Center-involved DME, where the swelling affects the very center of the macula, poses the greatest threat to reading vision and daily activities.
Who Is Affected and Risk Factors
In 2021, approximately 9.60 million people in the United States (26.43% of those with diabetes) had some form of diabetic retinopathy (PMC, 2023). Of those, about 1.84 million people (5.06% of those with diabetes) had vision-threatening diabetic retinopathy (PMC, 2023). The number of Americans with diabetic retinopathy is expected to nearly double from 7.7 million in 2010 to 14.6 million by 2050 (NEI).
Several factors increase the likelihood that a person with diabetes will develop retinopathy. Being aware of these risk factors helps identify patients who need earlier or more frequent screening.
- Duration of diabetes: people who have had diabetes for 15 years or more are over three times as likely to have diabetic retinopathy and more than 23 times as likely to have severe disease compared to those newly diagnosed (NEI)
- Chronic high blood sugar (poor glycemic control)
- High blood pressure (hypertension)
- High cholesterol and other lipid abnormalities (dyslipidemia)
- Kidney disease (nephropathy)
Pregnant women with pre-existing diabetes face an increased risk of rapid progression of diabetic retinopathy. These patients should receive an eye examination early in pregnancy and be monitored closely throughout. Women who develop gestational diabetes (diabetes that begins during pregnancy) do not require a separate eye exam for this condition.
Adolescents going through puberty may also experience accelerated progression of diabetic retinopathy. Closer follow-up during this stage of development is important. Additionally, studies have found that among people newly diagnosed with diabetes, nearly one in four may already have signs of diabetic retinopathy at the time of diagnosis (NEI).
Recent attention has focused on the possibility that rapid, tight blood sugar control may accelerate the onset of diabetic retinopathy. This has been observed with newer glucose-lowering medications such as semaglutide and similar agents. Patients starting these treatments may benefit from closer retinal monitoring, especially if they had previously uncontrolled blood sugar levels.
Signs and Symptoms
In its early stages, diabetic retinopathy may cause no noticeable symptoms. Many patients feel their vision is normal even when significant changes are occurring inside the eye. This is one of the main reasons routine screening is so important. Damage can accumulate silently before a person notices any change in sight.
As the disease progresses, patients may begin to notice changes in their vision. These can include blurred or fluctuating vision, dark spots or floaters, difficulty seeing at night, and faded or washed-out colors. If diabetic macular edema develops, patients may notice that straight lines appear wavy or that reading becomes more difficult.
Certain symptoms indicate a serious problem and require immediate evaluation by a retina specialist or a visit to the emergency room. These include a sudden increase in floaters, flashes of light, a shadow or curtain across part of the vision, or sudden vision loss in one eye. These could signal a vitreous hemorrhage (bleeding inside the eye) or a retinal detachment, both of which need prompt treatment to protect vision.
Diagnosis and Testing
People with type 1 diabetes should begin annual screening for diabetic retinopathy five years after their diagnosis. People with type 2 diabetes should have their first screening at the time of diagnosis and at least once every year after that. A retina specialist may recommend more frequent exams depending on the severity of any findings.
The standard method for detecting diabetic retinopathy is a comprehensive dilated eye exam. During this exam, drops widen the pupil so the retina specialist can see the inside of the eye clearly. The specialist looks for microaneurysms, bleeding, swelling, abnormal blood vessels, and other signs of damage.
Retina specialists may use additional tests to evaluate the health of the retina in more detail. Optical coherence tomography (OCT) creates cross-sectional images of the retina to measure swelling and detect fluid. Fluorescein angiography uses a special dye injected into a vein to reveal leaking or blocked blood vessels. Electroretinography (ERG), which measures the electrical response of the retina to light, has been included in the 2024 update of the AAO Preferred Practice Pattern Guidelines for diabetic retinopathy (AAO, 2024).
Treatment Options
Anti-VEGF medications are the primary treatment for center-involved diabetic macular edema with vision loss and for proliferative diabetic retinopathy. These medications block vascular endothelial growth factor, the protein that drives abnormal blood vessel growth and leakage. They are given as intravitreal injections (injections directly into the eye).
Several anti-VEGF agents are used in retina care. Eylea (aflibercept) is one of the most commonly used, typically given every four to eight weeks after initial loading doses. Eylea HD (high-dose aflibercept) was approved by the FDA with dosing intervals up to five months for DME (FDA, 2026). Lucentis (ranibizumab) was the first anti-VEGF medication approved for eye use and is typically given every four weeks. Vabysmo (faricimab), a bispecific antibody that targets both VEGF and angiopoietin-2, can be given at intervals of up to 16 weeks for some patients.
Avastin (bevacizumab) is FDA-approved for the treatment of certain cancers but is widely used off-label by retina specialists for diabetic macular edema and diabetic retinopathy. It works through the same VEGF-blocking mechanism as other anti-VEGF agents. It is typically given every four to six weeks. Patients should be aware that its use for eye conditions is off-label.
Susvimo (ranibizumab injection) 100 mg/mL is the first FDA-approved continuous delivery treatment for diabetic retinopathy. A small refillable implant is surgically placed in the eye and delivers medication continuously, with refills needed approximately every nine months. This option may reduce the number of office visits required for ongoing treatment.
Panretinal photocoagulation (PRP) is a laser surgery that remains an important treatment for proliferative diabetic retinopathy. During PRP, a retina specialist applies hundreds of small laser burns to the peripheral retina. This reduces the oxygen demand of the damaged retina and slows the growth of abnormal blood vessels. Focal or grid laser may also be used in some cases of diabetic macular edema.
Vitrectomy (a surgery to remove the gel inside the eye) may be needed when there is significant bleeding into the vitreous or when scar tissue causes traction on the retina. During this procedure, the retina specialist removes the vitreous gel along with any blood or scar tissue and replaces it with a clear solution or gas bubble to help the retina heal.
What to Expect
When diabetic retinopathy is detected and treated early, current treatment strategies may be up to 90% effective in preventing severe vision loss (NEI). Severe vision loss in this context means visual acuity worse than 5/200. Anti-VEGF injections can reduce the severity of diabetic retinopathy and in some cases cause the disease to improve on imaging. However, outcomes depend on how advanced the disease is at the time treatment begins.
Most anti-VEGF treatment visits take less than an hour. The eye is numbed with drops before the injection to minimize discomfort. Patients may experience mild soreness, redness, or a sensation of pressure after the injection. These effects typically resolve within a day or two. Ongoing treatment usually requires regular follow-up visits for monitoring and additional injections as needed.
Diabetic retinopathy is a chronic condition that requires long-term management. Even after successful treatment, regular follow-up exams are essential to watch for recurrence or progression. A retina specialist will determine the appropriate follow-up schedule based on the severity of the disease and the patient's response to treatment.
Living with Diabetic Retinopathy
Controlling blood sugar levels is one of the most important steps a person can take to slow the progression of diabetic retinopathy. Working with a primary care provider or endocrinologist to maintain healthy blood sugar, blood pressure, and cholesterol levels supports overall eye health. These efforts complement the treatments provided by a retina specialist.
Keeping all scheduled eye exams is critical. Because diabetic retinopathy can worsen without symptoms, skipping or delaying appointments can allow the disease to advance to a stage where treatment is less effective. Patients who notice any new vision changes between appointments should contact a retina specialist promptly rather than waiting for their next scheduled visit.
A diagnosis of diabetic retinopathy can cause worry and frustration. Patients may benefit from connecting with diabetes support groups or low-vision rehabilitation services if their sight has been affected. A retina specialist can provide guidance on available resources. Staying informed about the condition and actively participating in treatment decisions can help patients feel more confident about their care.
When to See a Retina Specialist
Primary care providers and optometrists play a vital role in identifying patients who need retina care. The following findings during a screening exam should prompt a referral to a retina specialist.
- Any level of macular edema detected on exam or imaging
- Severe nonproliferative diabetic retinopathy, which is a precursor to the proliferative stage
- Any proliferative diabetic retinopathy, including the presence of new abnormal blood vessels
- Visual acuity worse than 20/40 or patient reports of symptomatic vision changes
- Neovascularization of the iris or angle (new blood vessel growth in the front of the eye), which requires urgent referral
Not all referrals carry the same level of urgency. High-risk proliferative diabetic retinopathy, defined by larger areas of new vessel growth on the optic disc or any new vessel growth accompanied by bleeding, should be referred within 24 to 48 hours (AOA, 2019). Lower-risk proliferative disease may be referred within two to four weeks. Patients with anterior segment neovascularization (new vessel growth in the front part of the eye) should be referred urgently because prompt treatment may prevent severe complications such as neovascular glaucoma.
Certain patients benefit from earlier or more frequent retinal evaluations beyond the standard annual schedule. These include pregnant women with pre-existing diabetes, adolescents going through puberty, patients starting rapid glucose-lowering therapies such as semaglutide, and anyone with a history of poor blood sugar control or long-standing diabetes. When in doubt, referring to a retina specialist for a baseline evaluation is a reasonable and proactive step.
Questions and Answers
Yes. In its early stages, diabetic retinopathy often causes no symptoms at all. Significant changes to the retinal blood vessels can develop before a person notices any difference in their sight. This is why annual dilated eye exams are recommended for all people with diabetes, regardless of how well they feel they can see.
The rate of progression varies from person to person. In some cases, the disease may remain mild for years. In others, it can advance to a vision-threatening stage within months, especially if blood sugar, blood pressure, or cholesterol levels are poorly controlled. Pregnancy, puberty, and rapid changes in blood sugar control can also accelerate progression. Regular monitoring by a retina specialist helps detect changes before they become serious.
Before each injection, the eye is numbed with anesthetic drops. Most patients report feeling pressure or mild discomfort during the procedure rather than sharp pain. Some soreness, redness, or a gritty sensation may occur afterward and typically resolves within a day or two. While the idea of an eye injection can be concerning, most patients find the experience more manageable than they expected.
Without treatment, diabetic retinopathy can lead to permanent and severe vision loss. Proliferative disease can cause bleeding inside the eye, scar tissue formation, and retinal detachment. Diabetic macular edema can destroy central vision needed for reading, driving, and recognizing faces. Early detection and timely referral to a retina specialist offer the best chance of preserving vision.
There is growing evidence that rapid improvement in blood sugar control, including from medications such as semaglutide, may accelerate the development or progression of diabetic retinopathy in some patients. A retina specialist may recommend a baseline eye exam before starting these medications and closer follow-up during the first year of treatment. Patients should discuss this with both their diabetes care provider and their retina specialist.