A Systematic Review of Optic Disc Drusen in the Modern Imaging Era: Structure-Function Correlates, Diagnostic Performance, and NAION Co-Occurrence.

Background and Objectives: Optic disc drusen (ODD) can mimic papilledema and are linked to structural crowding, microvascular change, and visual-field loss. We synthesized structural/microvascular differences, functional status and change, diagnostic performance, and ODD-NAION co-occurrence. Methods: This study used PRISMA-aligned searches of PubMed, Embase, and Web of Science (inception-15 July 2025). Eligible designs included cross-sectional, cohort, and diagnostic accuracy studies with numeric outcomes (OCT/OCTA, visual fields, test accuracy, NAION prevalence). Two reviewers independently screened, extracted, and appraised bias. Heterogeneity precluded meta-analysis; narrative synthesis was used. Bias risk was moderate. Results: From 359 records, 6 studies met the criteria. ODD eyes showed thicker RNFL than controls (117.54 ± 18.75 vs. 105.81 ± 14.45 µm; 101 ± 12 vs. 97 ± 10 µm) and worse baseline mean deviation (-1.78 ± 3.87 dB). OCTA demonstrated sectoral peripapillary vessel-area density reduction (inferior 0.30 vs. 0.34; temporal 0.44 vs. 0.48; superonasal 0.44 vs. 0.49). Visual-field phenotypes were normal (44-52%), enlarged blind spot (19-29%), and other localized defects (24-29%); the longitudinal decline averaged -0.23 ± 0.26 dB/year with 88% slow progressors. In pseudopapilledema, single-test yields were ultrasound at 87.2%, OCT at 80.2%, and FAF at 62.8%; OCT alone distinguished buried ODD from mild papilledema with 50-64% accuracy (κ ≈ 0.35). Among young NAION, ODD affected 56.7% of patients and 53.3% of eyes; bilaterality was 95.2%, and only 35.9% were ophthalmoscopically visible. Conclusions: Multimodal imaging shows structural thickening, microvascular rarefaction, and modest functional loss in ODD, with slow average progression. In suspected papilledema, protocolized multimodal workflows outperform OCT alone. ODD are common in young NAION, supporting risk stratification and longitudinal monitoring.