Retinal vessel dynamics analysis as a surrogate marker for raised intracranial pressure in patients with suspected idiopathic intracranial hypertension.

Introduction: Retinal vessel dynamics analysis has proven to be a viable, non-invasive surrogate marker for increased intracranial pressure. We aimed to test this method in patients with suspected idiopathic intracranial hypertension.
Methods: Patients with suspected idiopathic intracranial hypertension were prospectively enrolled for hand-held fundus-videography during diagnostic lumbar puncture. After extracting optic disc images, peripapillary arteriole-to-venule-ratios were measured using machine-learning algorithms with manual identification control. A general linear model was applied to arteriole-to-venule-ratios and corresponding lumbar opening pressures to estimate cerebrospinal fluid pressure.
Results: Twenty-five patients were included with a significant difference in arteriole-to-venule-ratio between patients with ( n  = 17) and without ( n  = 8) idiopathic intracranial hypertension (0.78 ± 0.10 vs 0.90 ± 0.08, p  = 0.006). Arteriole-to-venule-ratio correlated inversely with lumbar opening pressure (slope regression estimate -0.0043 (95% CI -0.0073 to -0.0023), p  = 0.002) and the association was stronger when lumbar opening pressure exceeded 15 mm Hg (20 cm H ₂ O) (slope regression estimate -0.0080 (95% CI -0.0123 to -0.0039), p  < 0.001). Estimated cerebrospinal fluid pressure predicted increased lumbar opening pressure >20 mm Hg (27 cm H ₂ O) with 78% sensitivity and 92% specificity (AUC 0.81, p  = 0.02). A stand-alone arteriole-to-venule-ratio measurement predicting lumbar opening pressure >20 mm Hg (27 cm H ₂ O) was inferior with a 48% sensitivity and 92% specificity (AUC 0.73, p =  0.002).
Conclusion: Retinal vessel dynamics analysis with the described model for estimating cerebrospinal fluid pressure is a promising non-invasive method with a high sensitivity and specificity for detecting elevated intracranial pressure at follow-up assessments of patients with confirmed idiopathic intracranial hypertension if initial lumbar opening pressure and arteriole-to-venule-ratio data are available.