OCTA in Retinal Vascular Disease: Transformative Tool or Expensive Gimmick?

Retinal vascular diseases, including DR, RVO and RAO, contribute substantially to preventable vision loss. Assessment of perfusion, vascular integrity and neovascularization is central to diagnosis and management. FA has traditionally served as the reference method for dynamic assessment of retinal circulation, nonperfusion and leakage, but it is invasive, time-consuming and provides a two-dimensional projection of a three-dimensional vascular network. OCTA emerged to add noninvasive, depth-resolved vascular imaging to structural OCT.

Review question: Where does OCTA meaningfully improve diagnosis, disease staging, monitoring or prognostic assessment in retinal vascular disease, and where do its technical, clinical and economic limitations outweigh its incremental value?

• Noninvasive vascular imaging: OCTA visualizes flow-related decorrelation signals without intravenous dye injection.
• Depth-resolved assessment: Automated segmentation can display the superficial capillary plexus (SCP), deep capillary plexus (DCP), outer retina and choriocapillaris in separate en face slabs.
• Quantitative biomarkers: Common measures include vessel density, perfusion density and FAZ dimensions, alongside areas of capillary nonperfusion.
• Structural and vascular correlation: OCTA can be interpreted alongside cross-sectional structural OCT to relate microvascular changes to retinal anatomy.

OCTA acquires repeated OCT B-scans at the same location and uses motion-contrast algorithms to distinguish moving erythrocytes from static tissue. Algorithms include split-spectrum amplitude-decorrelation angiography (SSADA), optical microangiography (OMAG) and phase-based approaches. Their sensitivity to slow flow, noise and motion differs. Commercial devices can produce statistically different quantitative outputs, limiting direct comparison across platforms and studies.

Quantification is affected by acquisition protocols, segmentation boundaries, signal quality, thresholding and post-processing. Even small changes in signal quality can alter calculated metrics. Normative databases vary by device, and standardization is needed before small differences can be interpreted consistently across visits or populations.

• Flow detection thresholds: Very slow or turbulent flow may not be detected, potentially underestimating capillaries or neovascular complexes.
• No leakage information: OCTA does not directly show vascular leakage or permeability, limiting its ability to assess inflammatory activity and some manifestations of active disease.
• Field of view: Traditional scans focus on the posterior pole. Widefield and swept-source OCTA are expanding coverage, but peripheral assessment remains a consideration.
• Projection artifacts: Superficial vessel signals may appear in deeper plexuses.
• Motion and attenuation: Poor fixation, media opacity, hemorrhage and edema can degrade images or mimic capillary dropout.
• Segmentation errors: Retinal pathology can distort automated slab boundaries, so interpretation requires review of both en face images and cross-sectional scans.

• Early microvascular change: Reduced VD and subtle FAZ enlargement have been reported in some eyes without clinically apparent DR on fundus photography; the clinical implications of such early findings remain uncertain.
• Nonperfusion and severity: OCTA can quantify capillary nonperfusion, VD reduction, FAZ enlargement and plexus-specific disruption.
• Intraretinal microvascular abnormalities (IRMAs): The review describes associations between increasing IRMA burden and more severe nonproliferative DR, with unstable IRMAs associated with clinical progression in cited research.
• Microaneurysms: One cited study reported a 56% detection rate with high-speed OCTA versus 36% with color fundus photography; both were substantially below FA. The management value of microaneurysm quantification remains unclear.
• Neovascularization: In a cited ultra-widefield study, OCTA had 95% sensitivity for identifying eyes with retinal neovascularization, but detected only 67% of individual lesions seen on FA.
• Clinical status: These measures may support ischemia assessment, follow-up planning and research, but standardization and longitudinal validation remain necessary.

• Retinal vein occlusion (RVO): Macular and peripapillary measures—including VD, lacunarity, FAZ size and perifoveal capillary arcade disruption—have been associated with disease severity and peripheral ischemia measured by FA. DCP impairment has also been investigated as a marker for distinguishing ischemic from nonischemic central RVO.
• Potential prediction: OCTA abnormalities in clinically unaffected fellow eyes and machine-learning models using pre-onset images are being investigated for risk prediction; routine predictive use is not established.
• Laser planning: OCTA-guided treatment of nonperfused areas in branch RVO has been studied, but differences between planned and actual treatment areas require further refinement.
• Retinal artery occlusion (RAO): Studies generally report reduced VD in SCP and DCP, often with greater SCP involvement, although findings vary. VD has been correlated with visual acuity and used to assess vascular changes after experimental or emerging interventions.
• Clinical status: OCTA offers objective perfusion measures, but current clinical use in RAO is limited by established diagnostic pathways and the limited availability of treatments that reliably improve vision.

The noninvasive nature of OCTA may be particularly useful for patients requiring long-term monitoring, because it reduces cumulative exposure to dye angiography. Widefield OCTA and quantitative nonperfusion measures have been studied for staging and identifying proliferative disease. Longitudinal swept-source OCTA reports suggest macular ischemia may progress despite apparently stable peripheral retinopathy or visual function, including FAZ enlargement and declining macular VD.

A cited 2025 meta-analysis found an enlarged FAZ and reduced SCP and DCP VD in sickle cell retinopathy compared with controls, but associations with genotype, Goldberg stage and visual acuity were not consistent across studies. Pediatric findings are also mixed. Larger studies and standardized acquisition, analysis and outcomes are needed before these biomarkers can reliably guide care or predict systemic complications.

OCTA-capable systems require substantial capital investment. Although many platforms integrate OCTA into standard OCT systems, acquisition and interpretation add time and complexity, and reimbursement may not fully cover the additional work. Its value is greatest when it reduces invasive testing, increases diagnostic confidence, or provides prognostic information that changes follow-up or treatment planning. Where FA is readily available and infrequently repeated, the incremental benefit may be modest.

The review presents OCTA as an indispensable research tool with growing clinical promise, but stresses that evidence of a biomarker association does not automatically demonstrate improved patient outcomes or changed management.

OCTA has advanced understanding of retinal microvascular pathology and enabled layer-specific, noninvasive quantitative assessment across several retinal vascular diseases. It complements FA by offering depth-resolved flow imaging and measurements that FA cannot provide in the same way, while FA remains important for dynamic leakage assessment and for detecting lesions OCTA may miss. Wider fields of view, faster acquisition, improved artifact suppression, standardized protocols and AI-assisted analysis may increase utility. Ultimately, OCTA should be used as part of a comprehensive multimodal imaging strategy, with clinical decisions grounded in sound judgment and the limitations of each modality.

Mayeda MS, de Carlo Forest TE. Optical coherence tomography angiography in retinal vascular disease: transformative tool or expensive gimmick? Current Opinion in Ophthalmology. 2026;37(5):361–366. doi:10.1097/ICU.0000000000001223.