Advancements in Imaging Capillary Perfusion in Retinal Diseases

A new multimodal analysis quantifies intermittent capillary perfusion in RVO and PDR using OCTA plus dynamic fluorescein angiography. This advance ties measurable perfusion variability to tissue ischemia and to neovascular risk, offering a direct path to improved risk stratification.

OCTA provides capillary-level quantification while dynamic FA captures temporal dye transit, and the published comparison demonstrates different sensitivity to transient flow interruptions. Notably, OCTA is preferable when noninvasive, repeatable metrics of vessel density and flow-void frequency are required; in contrast, dynamic FA adds temporal resolution that reveals brief transit delays and focal perfusion recovery.

Those measurement differences matter because they change whether we measure sectoral ischemic index or dynamic perfusion variability. And so consistent acquisition and per-layer analysis are required for these metrics to be actionable.

The analysis reports that quantified intermittent perfusion metrics correlate with ischemia severity and with markers of neovascularization, linking higher GoPLoP (combined gain- and loss-of-perfusion metric; GoP = gain of perfusion, LoP = loss of perfusion) and perfusion variability to greater hypoxic burden.

In RVO, intermittent perfusion maps to a sectoral ischemic index and predicts focal neovascular risk; consequently, clusters of LoP/GoP and elevated flow-void frequency identify discrete retinal sectors at highest risk. In PDR, perfusion loss is more diffuse and the pattern of reduced vessel density plus sustained perfusion variability associates with widespread neovascular patterns; therefore, global ischemic index and lower perfusion density better reflect disease extent.

Integrating quantified perfusion into follow-up triggers can intensify monitoring cadence or prompt earlier anti-VEGF or targeted laser before frank neovascularization emerges. And so clinicians should consider standardizing metric definitions—vessel density, ischemic index, and flow-void quantification—and incorporating them into treatment-decision pathways and trial endpoints to translate these findings into care.