2026 Poster Presentations
P010: RETINAL NERVE FIBER LAYER (RNFL) THICKNESS: A SURROGATE FOR OPTIC NERVE AXONAL INTEGRITY AND COMPOSITE VISION OUTCOMES IN MEDIAN AND PARAMEDIAN SKULL BASE MENINGIOMAS
Reinier Alvarez1; Briana Hines2; Ariel Walker3; Andrew Mecum4; Yan Zhou4; John Butterfield1; Sera Sempson1; Omaditya Khanna5; Aria Mahtabfar1; Rachel Blue6; Prem Subramanian7; Samy Youssef1; 1University of Colorado Anschutz School of Medicine, Department of Neurosurgery; 2Tulane School of Medicine; 3Wayne State University School of Medicine; 4University of Colorado Anschutz School of Medicine; 5Wake Forest School of Medicine, Department of Neurosurgery; 6University of Pennsylvania School of Medicine, Department of Neurosurgery; 7University of Colorado Anschutz School of Medicine, Department of Ophthalmology
Introduction: Median and paramedian skull base (SB) meningiomas intimately involve the optic nerve. Mass effect on the cisternal optic nerve and optic canal invasion cause a compressive optic neuropathy with eventual vision loss. Post-operative vision improvement rates range from 10% to 80%, however, post-operative worsening has been reported in 2% to >30% of cases. Predictors of post-operative vision such as symptom duration, prior treatment, and tumor size have been described, but with inconsistent results. Prior studies of compressive pathologies, primarily pituitary adenomas, suggest preserved retinal nerve fiber layer (RNFL) thickness on optical coherence tomography (OCT) correlates with favorable visual outcomes as it reflects retinal ganglion cell axonal integrity. As identifying reliable factors is essential for counseling and surgical planning, we evaluated whether preoperative RNFL thickness can predict post-operative composite vision outcomes in median and paramedian SB meningiomas.
Methods: We retrospectively analyzed patients with median and paramedian SB meningiomas who underwent pre- and post-operative neuro-ophthalmologic assessment (n=66). Patients were stratified into those with standardized OCT evaluation at the primary institution (n=48) and those with outside OCT evaluation (n=18), ensuring serial measurements on the same device. Central vision assessed by visual acuity (VA, Snellen, converted to LogMAR) and peripheral vision by Humphrey visual field (VF) mean deviation (MD). OCT measured peripapillary RNFL thickness (µm). Composite vision quantified using the German Ophthalmological Society Visual Impairment Scale (VIS, range 0–100). Vision improvement was defined as ≥2-line VA gain, VF MD improvement ≥2 dB, or decreased VIS score. Eyes were classified as “normal” or “thin” RNFL based on device normative databases. Correlation and multivariate analyses evaluated associations between RNFL and outcomes.
Results: Sixty-six patients (133 eyes) met inclusion. Mean age was 54.4±13.6 years; 68.8% were female. Tumors were paramedian in 58.8%, with sphenocavernous (15%) and spheno-orbital (12%) most common. Among median tumors, tuberculum sellae were most common (25.8%). Mean tumor diameter measured 3.3±1.5 cm; 64% had optic canal invasion. Three patients were legally blind preoperatively. Six patients underwent endonasal and the remainder transcranial approaches. Preoperatively, 32% of eyes had thin RNFL (mean 65.6±12.5 µm) with worse vision (median LogMAR 0.56, VF MD −19.0±12.2). Eyes with normal RNFL (mean 99.8±8.9 µm) had better vision (median LogMAR −0.12, VF MD −3.9±8.5). Postoperatively, VA improved by ≥2 lines in 20% of eyes, VF improved by ≥2 dB in 33%, and all three blind patients improved beyond legal blindness. Thin RNFL eyes showed the greatest variability in VF change (median ΔMD 1.28, range −32.7 to +27.6). Higher preoperative RNFL thickness correlated with better composite outcomes (p=0.01). Each 1 µm increase in RNFL corresponded to a 0.53-point VIS decrease (p=0.01). No absolute value reliably separated favorable from unfavorable outcomes.
Conclusion: Preoperative RNFL thickness may predict post-operative vision in median and paramedian SB meningiomas. Normal RNFL was significantly more likely to recover vision, consistent with prior studies in pituitary tumors. OCT-based RNFL assessment should be standardized and incorporated into the pre-surgical evaluation of median and paramedian SB as it shows promise as a prognostic biomarker.