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OCT Angiography: Dye-Free Imaging of Your Retina
Why This Test Matters for Your Eye Health
Many retinal diseases develop quietly, affecting blood vessels in ways that are not visible during a standard eye exam and that cause no noticeable symptoms in their early stages. OCTA gives our team the ability to see these changes early, measure them precisely, and respond with targeted treatment. Its speed, safety, and depth of detail make it an essential part of modern retinal care.
In conditions like diabetic retinopathy, vascular changes can begin years before a patient notices any vision loss. OCTA can identify early reductions in capillary density, changes in the foveal avascular zone, or areas of poor blood flow that would otherwise go undetected. Catching these changes early gives us more options for protecting your vision.
Because OCTA is quick and does not require dye, it can be repeated at regular intervals without risk or significant inconvenience. This makes it an ideal tool for monitoring how a condition evolves over time. Your retina specialist can compare scans from one visit to the next, looking at measurable values such as vessel density and FAZ area, to determine whether your condition is stable, improving, or progressing.
OCTA findings directly influence treatment decisions. The images can reveal areas of reduced blood flow, abnormal new blood vessel growth (a process called neovascularization), and tiny bulges in vessel walls called microaneurysms. Each of these findings may point toward a different course of action. When neovascularization is identified, for example, it may signal the need for anti-VEGF injection therapy, medications that block the protein responsible for driving abnormal vessel growth.
Conditions We Evaluate with OCTA
OCT angiography has become a standard diagnostic tool across a wide range of retinal conditions. Our team uses it to evaluate new diagnoses, confirm suspected findings, and keep a close watch on diseases that require ongoing management. Below are the conditions where OCTA plays a particularly important role in our practice.
In wet age-related macular degeneration (AMD), abnormal blood vessels grow beneath or within the retina in a process called macular neovascularization. OCTA can identify these abnormal vessels without dye injection, helping confirm a diagnosis and monitor how well treatment is working. Anti-VEGF medications used for wet AMD include Avastin (bevacizumab), Lucentis (ranibizumab), Eylea (aflibercept), and Vabysmo (faricimab). OCTA helps our team evaluate whether these vessels are shrinking, remaining stable, or continuing to grow in response to treatment.
In dry AMD, OCTA can reveal changes in the choriocapillaris that may indicate areas at higher risk for progression to geographic atrophy, an advanced stage of dry AMD in which retinal cells are permanently lost. For patients with geographic atrophy, Izervay (avacincaptad pegol) is an approved treatment that can slow progression, though it does not restore vision that has already been lost. OCTA supports ongoing monitoring of these patients over time.
Diabetes can damage the small blood vessels of the retina over time, a condition known as diabetic retinopathy. OCTA provides detailed maps of this damage, showing areas where vessels have been lost, where blood flow is reduced, and where abnormal new vessels have begun to grow. These images help our team grade the severity of the condition and plan appropriate treatment, whether that involves laser photocoagulation, anti-VEGF injections, or continued monitoring.
Specific OCTA measurements, including vessel density and foveal avascular zone size, serve as objective markers of retinal health in patients with diabetes. Tracking these numbers over time gives our retina specialists a reliable way to assess whether the condition is progressing or responding to care.
A retinal vein occlusion is a blockage in one of the veins that drains blood from the retina. This blockage can cause swelling, bleeding, and significant vision loss. OCTA helps our team map the extent of the vascular damage, identify areas of poor blood flow, and detect any abnormal new vessels that may have formed in response to the blockage. This information guides decisions about treatment and follow-up imaging intervals.
OCTA is also useful for evaluating several additional conditions that affect retinal blood vessels. Each of these conditions involves changes to vessel structure or blood flow that OCTA can capture in detail.
- Retinal artery occlusion, a blockage in an artery supplying the retina
- Uveitis, inflammation inside the eye that can affect retinal blood vessels
- Macular telangiectasia, an abnormal widening of small blood vessels near the center of the retina
In each of these cases, OCTA provides structural information that helps our team make more confident diagnostic and treatment decisions.
What to Expect During Your OCTA Appointment
Knowing what will happen before, during, and after your scan helps you feel prepared and comfortable at your visit. The process is straightforward and involves no injections, no radiation, and no recovery time. Most patients find the experience quick and entirely painless.
In most cases, your eyes will be dilated with eye drops before the OCTA scan. Dilation widens your pupil so the imaging device can capture a clearer, more complete image of your retina. The drops take approximately 15 to 30 minutes to take full effect. Your vision may be temporarily blurry and your eyes may be sensitive to light for a few hours after dilation, so bringing sunglasses to your appointment is a good idea.
No fasting is required before your visit, and you may take your regular medications as usual. If you wear contact lenses, you may be asked to remove them before the scan.
The scan itself is quick and comfortable. You will sit in front of the imaging device and rest your chin on a support. A technician will ask you to focus on a small target light inside the machine. The device scans your retina using infrared light, which you cannot feel at all. Each eye typically takes only a few minutes to image.
Keeping your gaze steady on the target light is important. Movement during the scan can introduce artifacts (distortions in the image) that may affect image quality. If this happens, the technician may simply repeat the scan.
There is no recovery time associated with the OCTA scan itself. If your eyes were dilated, the effects of the drops will wear off within a few hours. Your retina specialist will review the images and discuss the findings with you, often at the same appointment. All images are stored digitally and can be compared with future scans to track any changes in your retinal health over time.
Benefits and Limitations of OCTA
OCTA is a significant advancement in retinal diagnostics, but like any imaging technology it has both strengths and limitations. Understanding both helps set realistic expectations and explains why your retina specialist may occasionally combine OCTA with other imaging tests for a more complete assessment.
OCTA offers several meaningful benefits over older imaging methods, particularly for patients who require frequent monitoring or who cannot tolerate dye injections.
- No dye injection is required, eliminating the risk of allergic reactions associated with fluorescein angiography
- The scan is fast, typically completed in just a few minutes per eye
- It provides depth-resolved images, allowing separate visualization of distinct vascular layers
- Results are available immediately and are often reviewed during the same visit
- The test can be repeated as frequently as needed without added risk or discomfort
OCTA is a powerful diagnostic tool, but it does have limitations that are important to understand. Most notably, OCTA cannot detect leakage from blood vessels. When active leakage is a key part of the diagnostic question, fluorescein angiography may still be necessary to provide that information.
Image quality can also be affected by patient movement, which can cause artifacts such as vessel duplication or discontinuity. Cataracts or other conditions that cloud the lens can interfere with the imaging signal as well. Additionally, measurements from one type of OCTA device may not be directly comparable to measurements from another, which is why consistent use of the same imaging platform over time is preferred for monitoring purposes.
One specific imaging artifact worth understanding is called a projection artifact. This occurs when the signal from blood vessels in the superficial retinal layers is inadvertently projected onto deeper layers in the image, making it appear as though vessels exist where none are actually present. Modern OCTA software includes tools to reduce this effect, and our retina specialists are trained to recognize and account for it when interpreting your scan results.
Frequently Asked Questions
Below are answers to common questions patients ask about OCT angiography. If you have questions that are not covered here, our team is happy to walk you through anything before or after your appointment.
Yes, OCTA is a safe option for patients with a history of allergic reactions to fluorescein dye or other contrast agents. The scan uses only infrared light and requires no injected substance of any kind. If you have had a prior reaction to dye during an eye imaging test, be sure to let your retina specialist know so the appropriate imaging plan can be made for you.
In many cases, yes. OCTA can detect subtle reductions in vessel density, changes in the foveal avascular zone, and areas of abnormal blood flow well before these changes affect your vision. This is especially valuable for patients with diabetes or other risk factors for retinal disease, where early detection can meaningfully change the outcome of treatment. Waiting for symptoms to appear means waiting until damage has already occurred.
For many patients, OCTA has replaced fluorescein angiography as the primary imaging tool. However, because OCTA cannot show vascular leakage, fluorescein angiography remains necessary for certain diagnostic situations. Your retina specialist will decide which test or combination of tests gives the most useful information for your specific condition. In some cases, both may be performed at the same visit.
The frequency depends on your diagnosis and how stable your condition is. Patients with actively treated conditions such as wet AMD or diabetic macular edema may need imaging at every visit to monitor treatment response. Patients in a monitoring phase with a stable condition may need scans less often. Your retina specialist will recommend a follow-up schedule based on your individual situation and may adjust it as your condition changes.
Certain symptoms require prompt evaluation and should not wait for a routine imaging appointment. These include a sudden increase in floaters, flashes of light in your vision, a dark curtain or shadow spreading across your field of view, or sudden vision loss in one or both eyes. These can be signs of a retinal tear or detachment, which is a medical emergency. Contact our office immediately or go to the nearest emergency room if you experience any of these symptoms.
No. OCTA uses infrared light to image the retina, not radiation. It is safe to undergo repeatedly over time, which is one reason it has become such a useful monitoring tool for chronic retinal conditions. The scan does not touch your eye and produces no heat or other physical sensation.
Expert Retinal Care on the Delmarva Peninsula
Atlantic Retina Center is a single-specialty vitreoretinal practice, meaning our entire focus is the retina, vitreous, and macula. Our fellowship-trained, board-certified retina specialists use OCT angiography alongside a full range of advanced imaging tools to give you the most accurate, up-to-date assessment of your retinal health. If you have been referred for retinal imaging or have concerns about your vision, we encourage you to schedule a visit and experience the difference that focused, specialized care makes.