Is Your Glaucoma Diagnosis Missing Something? Macular vs. Peripapillary Scans
"Discover why peripapillary vessel analysis could be the key to earlier and more accurate glaucoma detection."
Glaucoma, a leading cause of irreversible blindness, is characterized by the progressive loss of retinal ganglion cells (RGCs) and their axons, impacting the retinal nerve fiber layer (RNFL). Early and accurate diagnosis is crucial to slowing its progression, typically involving optic disc evaluation, visual field tests, and Optical Coherence Tomography (OCT) scans.
Recent studies suggest that early glaucoma damage is detectable through OCT as reduced RNFL thickness in the peripapillary region or thinning of the ganglion cell complex within the macula. However, the diagnostic performance of macular versus peripapillary vessel parameters remains variable, leading to questions about the most effective approach for early detection.
This article explores how assessing vessel parameters in both the macular and peripapillary regions, using Spectral-Domain Optical Coherence Tomography Angiography (SD-OCTA), can improve the differentiation between primary open-angle glaucoma (POAG) and healthy eyes, offering new insights into early diagnosis.
Visual Fields and Structural Scans
Standard automated perimetry (SAP) is a computerized static threshold visual-field test using a white stimulus on a white background, and it is recommended for glaucoma management. Visual-field testing is used both for diagnosis and follow-up, yet a 2025 review notes that limitations of SAP matter for diagnosing and managing diseases of the visual pathway, including glaucoma. OCT angiography studies have also examined 6 × 6-mm scans centered on the macula and optic nerve head in people with primary open-angle glaucoma (POAG) and healthy subjects.
From Ancient Descriptions to Quantitative Diagnosis
Hippocrates’ Aphorisms, published in 400 BC, contain the earliest known record identified as glaucoma, describing “glaucosis” associated with dim vision and eventual blindness. The historical review cautions that ancient accounts matching modern glaucoma most likely described acute angle-closure glaucoma, whose severe symptoms and rapid, irreversible blindness attracted medical attention. A 2018 review chronicles the shift from glaucoma diagnosis’s subjective ancient origins toward the modern goal of objective, precise, quantitative diagnostics.
Peripapillary vs. Macular: Why Location Matters in Glaucoma Detection
A recent study compared the diagnostic capabilities of vessel parameters in the macular and peripapillary regions, using SD-OCTA to differentiate POAG from healthy eyes. The study involved 126 eyes from 79 participants, including both POAG patients and healthy subjects, undergoing 6 x 6-mm scans centered on the macula and optic nerve head. Researchers analyzed vessel area density (VAD), vessel skeleton density (VSD), vessel complexity index (VCI), and flux in both regions.
- VAD (Vessel Area Density): The cpAUC (peripapillary area under the curve) was 0.84, while the mAUC (macular area under the curve) was 0.73 (P = 0.026).
- VSD (Vessel Skeleton Density): The cpAUC was 0.84, and the mAUC was 0.72 (ΔΡ = 0.015).
- VCI (Vessel Complexity Index): The cpAUC was 0.80, and the mAUC was 0.70 (ΔΡ = 0.045).
- Flux: The cpAUC was 0.87, and the mAUC was 0.76 (ΔΡ = 0.0091).
OCTA Vessel Density and Diagnostic Research
A review of OCT angiography reports that peripapillary vessel-density parameters—especially the inferotemporal sector measurement—showed good diagnostic ability in POAG and primary angle-closure glaucoma (PACG). A 2024 article describes glaucoma as progressive optic neuropathy involving structural damage and/or abnormal blood perfusion in the optic nerve head. It also reports that diagnosis and treatment of primary open-angle glaucoma suspects can be difficult, noting that 8.8% of suspects in the cited evidence progressed to visual-field defects.
Limits in Evidence and the Patient Pathway
The OCT angiography comparison study identifies its case-control design as a limitation because it prevents full application of its findings to a true clinic population. It also flags eye drops and glaucoma procedures as potential confounders of retinal microcirculation. A 2026 review describes delayed presentation or diagnosis and poor treatment adherence as challenges to glaucoma management, while an expert panel notes that diagnostic pathways and responsibilities vary across nations.
Macular and Peripapillary Measures
A meta-analysis summarized in a study comparing choroidal thickness reports that Zhang et al found no association between glaucomatous optic neuropathy and choroidal thickness across studies of macular or peripapillary measurements using SD-OCT and SS-OCT. The same source contrasts this with Lin et al’s meta-analysis, which found significantly decreased peripapillary choroidal thickness in open-angle glaucoma. Separately, a cross-sectional case-control study set out to compare the glaucoma-discriminating ability of macular nerve fiber layer thickness with total macular thickness and peripapillary nerve fiber layer thickness.
Improving Glaucoma Detection: What's Next?
The study confirms that peripapillary perfusion parameters outperform macular perfusion parameters in glaucoma diagnosis, reinforcing the understanding that glaucomatous vascular changes are more evident in the peripapillary region.
AI, Biomarkers, and Personalized Care
A 2025 review explores emerging glaucoma-care trends that include integrating artificial intelligence into OCT analysis, using biomarkers for early detection, and moving toward personalized treatment strategies. Another 2025 review describes early detection as critical to reducing the risk of irreversible vision loss and focuses on integrating advances in diagnosis and treatment. These sources present AI-assisted imaging, biomarkers, and personalization as areas of current attention rather than established outcomes.
This translational relevance emphasizes the need for clinicians to prioritize peripapillary region analysis when using OCTA for glaucoma assessment. Future research should focus on optimizing imaging algorithms and exploring other factors influencing retinal perfusion to enhance diagnostic accuracy.
By refining our diagnostic approaches and deepening our understanding of retinal perfusion, we can move towards earlier and more effective glaucoma detection, ultimately preserving vision for more individuals at risk.