OCT Imaging in Patients with Idiopathic Intracranial Hypertension: Explorations, Issues, Technical Difficulties and Nordic IIHTT Baseline Results

Papilledema due to intracranial hypertension is typically measured using fundus photography with Frisn scale noncontinuous ordinal staging. OCT, an additional objective method, measures papilledema changes on a continuous interval scale by quantifying the volume of optic nerve, the degree of RNFL and retina swelling, and to monitor treatment effects. High definition spectral OCT (SD-OCT) methods,such as a cube volume scans for data collection, give flexibility to find the exact measures of interest and increase resolution and scanning speed to acquire data over a wider area reducing sampling errors. Coupling these advances with new algorithms based on 3D volume appears to improve segmentation reproducibility and quantificiation of papilledema and RNFL alterations (Wang 2012) and improve quantitative assessments of optic disc changes in papilledema, including volumetric analysis by OCT and digital morphometric analysis of stereo photo images (Scott 2010; Echegaray 2011; Tang 2012)10-12. OCT imaging of papille ema was performed as a substudy of the IIHTT that included exploration of new approaches of analyzing the structural effects of papilledema and the peripapillary retina. These methods should overcome the limitations associated with swelling of the optic nerve head and the peripapillary retina (Mandel G, et al. IOVS 2010;51:ARVOEAbstract 555). This study compared Frisn scale, OCT volumetric determinations, and disc morphometry from photographs for subjects enrolled in the IIHTT at baseline and over time and relate the findings to clinical parameters such as visual acuity, HVF mean deviation, and spinal fluid opening pressure.