Optical Coherence Tomography and Optical Coherence Tomography Angiography-Derived Retinal Microvascular and Neuroretinal Measures in Adults With Ischemic Stroke and Carotid Artery Stenosis: A Systematic Review and Meta-Analysis.

Adults with ischemic stroke or carotid artery stenosis may exhibit retinal microvascular and neuroretinal changes that can be assessed non-invasively using optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). This systematic review and meta-analysis evaluated OCT- and OCTA-derived retinal microvascular and neuroretinal measures in these populations. Eligible original studies were synthesized narratively. Quantitative synthesis was limited to continuous outcomes with sufficiently similar anatomical and imaging definitions and extractable means, standard deviations, and sample sizes for both cerebrovascular disease and comparator groups. Deep retinal vessel density showed a moderate pooled standardized difference, with lower average measurements in the cerebrovascular disease groups and moderate heterogeneity detected. The retinal nerve fiber layer (RNFL)/peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell complex (GCC)/ganglion cell layer (GCL) analyses showed small pooled standardized differences, with no heterogeneity detected; however, each analysis included only three comparisons. Superficial and radial peripapillary or optic disc vessel density measurements were also lower on average, but substantial to high between-study heterogeneity limited uniform interpretation. The foveal avascular zone (FAZ) area analysis included only two comparisons and was considered exploratory. Separate small observational studies reported associations involving FAZ morphology, retinal vascular orientation, cerebral hemodynamics, and post-revascularization perfusion changes; however, these findings represent distinct hypothesis-generating signals and do not establish OCTA as a validated surrogate for cerebral perfusion or demonstrate a unified clinical pathway. Overall, OCT- and OCTA-derived retinal measures may help characterize group-level differences in selected retinal microvascular and neuroretinal measurements among adults with ischemic stroke or carotid artery stenosis, but these measures have not been validated for diagnostic or prognostic use. The review was not prospectively registered. Most included studies had moderate risk-of-bias concerns, while two were rated as moderate-to-high risk. The evidence was further limited by predominantly observational designs, variation in imaging protocols and comparator structures, and sparse quantitative evidence for several outcomes. Further prospective studies using standardized OCT and OCTA acquisition, segmentation, and reporting methods are required before these measures can support routine clinical interpretation or risk stratification.