Once limited to the macula, OCT angiography is widening its gaze to reveal ischemia, neovascularization and subtle signs of progression before they reach the center. With sharper detail and broader scope, the technology is changing how clinicians map, monitor and manage diabetic eye disease.
Sometimes progress begins by stepping back. For decades, diabetic retinopathy (DR) was mapped through a tight, macula-centered view that left much of the retina out of frame.
Now, with widefield optical coherence tomography angiography (OCT-A), clinicians are seeing the full circulation: the distant capillaries, the pockets of ischemia, the earliest neovascular sprouts. What once looked stable from the center is now revealed as dynamic and evolving at the periphery.
Zooming out on diabetic eye disease
Diabetic retinopathy used to be studied through a keyhole. Now, the lens has widened and the view keeps getting bigger.
The earliest stress signals often appear in the retinal periphery, where areas of non-perfusion forecast later macular decline.1 Widefield OCT-A pulls those distant regions into the picture, charting microvascular change that used to slip beyond the frame.2
“Color fundus imaging is our gold standard for monitoring disease stages. It is quick, it is noninvasive and we can use it to stage disease severity,” said Dr. Andreas Pollreisz (Austria) during his EURETINA 2025 lecture.2 “But on OCT angiography, you see much more detail because there is no leakage, and you can visualize the swollen capillaries at high lateral resolution.”
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The secret lies in motion contrast. OCT-A captures multiple scans within milliseconds at the same retinal spot, then calculates the signal differences that trace blood flow.3 The result is a dye-free, depth-resolved map of circulation that can expose early remodeling invisible on fundus imaging.
Expanding the field still brings trade-offs. “So far, we have a limited field of view,” explained Dr. Pollreisz. “When we go beyond the posterior pole, we face certain compromises. A wider capture needs longer acquisition time, which increases motion artifacts, and there are trade-offs in image quality and resolution. All of these factors need to be considered together.” Even so, 65° single-capture and 24 × 20 mm² systems already reach far beyond the macula, and research prototypes keep stretching toward true ultra-widefield coverage.4,5
Fluorescein angiography (FA) still draws the roadmap, but OCT-A offers the return trip: quicker, cleaner and needle-free. Use fluorescein to lay out the map and use widefield OCT-A to revisit it often, with more layers and less friction.
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Edges that tell the story
The periphery often writes the plot. Ultra-widefield FA first showed that retinal non-perfusion tracks with worsening disease and treatment need.1 Widefield OCT-A now measures the same story without dye, using an ischemic index (the non-perfused area divided by total area) to turn pictures into prognostics.
“Retinal non-perfusion in the periphery is significantly associated with the stage of diabetic retinopathy,” Dr. Pollreisz noted. “Higher stages need more extensive non-perfusion.”
Eyes with predominant peripheral lesions show a higher ischemic index and are more likely to develop macular edema (ME) or require anti-VEGF or panretinal photocoagulation (PRP).6 For clinicians, that means these patients need tighter follow-up and earlier intervention. The periphery isn’t the background. It’s the plot twist that tells you what happens next.
Bringing hidden lesions into focus
Some lesions look alike in a snapshot but tell very different stories over time. OCT-A can separate the characters. “A very useful application for quick and easy, non-invasive imaging is using OCT angiography to differentiate between intraretinal microvascular abnormalities [IrMA] and neovascularization,” said Dr. Pollreisz. “When flow extends into the vitreous, that’s neovascularization. If it stays below the internal limiting membrane, it’s IrMA.”
READ MORE: Functional Red Flags
The “ILM [internal limiting membrane]-breach” rule developed in 2020, when researchers showed that OCT-A could objectively flag whether vessels crossed that invisible boundary.7 This turned a subjective call into a clear diagnostic line, giving clinicians an objective, reproducible way to classify vascular change.
Longitudinal OCT-A adds motion to the picture, showing neovascular regression after anti-VEGF, quiescence after PRP and architectural repair post-surgery.8 Think of it less as a still life, more as a live feed of the retina’s recovery arc.
Seeing what the eye can’t
Some of the most telling features are invisible to the naked eye. Widefield OCT-A has revealed subclinical neovascularization, those delicate proliferations that slip past ophthalmoscopy and fundus photography. In one study, graders detected such hidden lesions in 19% of eyes graded as non-proliferative by conventional criteria.9
Coverage is everything. A 65° single-capture system demonstrated 95% sensitivity for detecting proliferative DR, showing that peripheral reach is crucial for reliable diagnosis.10 When those hidden lesions appear, they often coincide with mid-peripheral ischemia—an early warning that the disease is poised to advance.2
In practical terms, OCT-A doesn’t just widen the frame. It stretches the timeline, letting clinicians preview where the disease is heading rather than just where it’s been.
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When fluorescein still holds the map
For all its panoramic power, OCT-A still works best with a travel companion. “Fluorescein angiography is still necessary when we need to visualize the full retinal extent, which we cannot always achieve with widefield OCT angiography,” Dr. Pollreisz said. “We usually perform a baseline FA that guides us to suspicious lesions we can then follow with OCT-A.”
That tandem approach mirrors the American Society of Retina Specialists (ASRS) 2024 guidelines, which frame multimodal imaging as the new standard.11 Fluorescein offers the grand map and leakage timeline, whereas OCT-A supplies repeatable, depth-resolved detail.12 Reducing dye exposure also spares patients from the small but real risk of allergic reactions to fluorescein.13
It’s less a rivalry and more a relay in which fluorescein draws the map and OCT-A updates it in real time. And because OCT-A is fast, dye-free and endlessly repeatable, it turns follow-up visits into ongoing surveillance rather than staged events. The multimodal strategy of one map and many revisits mirrors how retina specialists work today: focused, efficient and using each tool for what it does best.
The horizon line
Each generation of widefield OCT-A pushes the edge outward while cutting acquisition time and motion blur. What began as a research luxury is fast becoming standard practice.
Fluorescein may keep its compass role, but OCT-A provides the panorama, the wide shot that gives every close-up its context. The view will continue to widen, but the goal isn’t just a bigger picture. It’s a sharper one, where every corner of the retina contributes to understanding the whole. In the evolving story of diabetic retinopathy, the view is finally big enough to match the disease.
Editor’s Note: Dr. Andreas Pollreisz’s insights in this article are based on his Day 4 presentation at EURETINA 2025 Paris, titled “OCT-A Widefield Imaging: Must Have or Nice to Have?”. This content is intended exclusively for healthcare professionals. It is not intended for the general public. Products or therapies discussed may not be registered or approved in all jurisdictions, including Singapore. A version of this article was first published in PIE Issue 37.
References
- Silva PS, Marcus DM, Liu D, et al. Association of ultra-widefield fluorescein angiography–identified retinal nonperfusion and the risk of diabetic retinopathy worsening over time. JAMA Ophthalmol. 2022;140(10):936-945.
- Pollreisz A. OCT-A Widefield Imaging: Must have or nice to have? Lecture at EURETINA 2025. Paris, France. September 7, 2025.
- Sun Z, Yang D, Tang Z, et al. Optical coherence tomography angiography in diabetic retinopathy: An updated review. Eye (Lond). 2021;35(1):149-161.
- Zeng QZ, Li SY, Yao YO, et al. Comparison of 24×20 mm² swept-source OCTA and fluorescein angiography for the evaluation of lesions in diabetic retinopathy. Int J Ophthalmol. 2022;15(11):1798-1805.
- Xia F, Hua R. The latest updates in swept-source optical coherence tomography angiography. Diagnostics. 2024;14(1):47.
- Stino H, Huber KL, Niederleithner M, et al. Association of diabetic lesions and retinal nonperfusion using widefield multimodal imaging. Ophthalmol Ret. 2023;7(12):1042-1050.
- Arya M, Sorour O, Chaudhri J, et al. Distinguishing intraretinal microvascular abnormalities from retinal neovascularization using optical coherence tomography angiography. Retina. 2020;40(9):1686-1695.
- Russell JF, Shi Y, Hinkle JW, et al. Longitudinal wide field swept source OCT angiography of neovascularization in proliferative diabetic retinopathy after panretinal photocoagulation. Ophthalmol Ret. 2019;3(4):350-361.
- Tsuboi K, Mazloumi M, Guo Y, et al. Utility of en face OCT for the detection of clinically unsuspected retinal neovascularization in patients with diabetic retinopathy. Ophthalmol Ret. 2023;7(8):683-691.
- Stino H, Niederleithner M, Iby J, et al. Detection of diabetic neovascularisation using single-capture 65°-widefield optical coherence tomography angiography. Br J Ophthalmol. 2024;108(1):91-97.
- Ramakrishnan MS, Kovach JL, Wykoff CC, et al. American Society of Retina Specialists Clinical Practice Guidelines on Multimodal Imaging for Retinal Disease. J Vitreoretin Dis. 2024;8(3):234-246.
- Parravano M, Cennamo G, Di Antonio L, et al. Multimodal imaging in diabetic retinopathy and macular edema: An update about biomarkers. Surv Ophthalmol. 2024;69(6):893-904.
- Kornblau IS, El-Annan JF. Adverse reactions to fluorescein angiography: A comprehensive review of the literature. Surv Ophthalmol. 2019;64(5):679-693.
