Researchers recently used OCT of the optic nerve head to quantify a new noninvasive biomarker of intracranial pressure (ICP): papilledema, one of ICP’s ocular manifestations.

The longitudinal cohort study included data from three randomized clinical trials conducted between 2014 and 2019. Study participants included 104 females with active idiopathic intracranial hypertension in the United Kingdom. The researchers performed automated perimetry and OCT imaging followed by ICP measurement on the same day. The first cohort (n=15, mean age 28.2) received continuous sitting telemetric ICP monitoring on one visit; the second cohort (n=89, mean age 31.8) underwent lumbar puncture assessment of ICP and was evaluated at baseline and at three, 12 and 24 months.

The researchers used an OCT protocol that included peripapillary retinal nerve fiber layer, optic nerve head and macular volume scans. They correlated the OCT measures of the optic nerve head and macula with ICP levels, Frisén grading and perimetric mean deviation.

The researchers found that optic nerve head central thickness was closely associated with ICP in the first cohort. The second cohort similarly revealed a correlation between central thickness and ICP longitudinally at 12 and 24 months. Overall, they found a positive association between central thickness and change in ICP at all points; a decrease in central thickness of 50μm was associated with a decrease in ICP of 5cm H2O.

The researchers concluded that optic nerve head volume measures on OCT, especially central thickness, “reproducibly correlated with ICP and surrogacy analysis demonstrated its ability to inform ICP changes.” They determined that OCT is useful for monitoring papilledema as well as noninvasively predicting ICP levels in idiopathic intracranial hypertension.

Vijay V, Mollan SP, Mitchell JL, et al. Using optical coherence tomography as a surrogate of measurements of intracranial pressure in idiopathic intracranial hypertension. JAMA Ophthalmol. October 22, 2020. [Epub ahead of print].