Optic Nerve Sheath Diameter as a Marker of Elevated Intracranial Pressure in Preeclampsia Compared to Controls

Preeclampsia may be complicated by cerebral edema and elevated intracranial pressure (ICP), yet magnetic resonance imaging is not always feasible for urgent or serial assessment. Ultrasonographic optic nerve sheath diameter (ONSD) measurement is a bedside surrogate that may reflect ICP-related changes.

To compare ONSD values among nonpregnant healthy women, normotensive pregnant women, and women with preeclampsia (with and without severe features), and to evaluate the discriminative performance of ONSD for hypertensive disorders of pregnancy.

This single-center retrospective cohort study (January 2021-January 2025) included 79 participants: nonpregnant healthy women ( n = 19), normotensive pregnant women ( n = 20), preeclampsia ( n = 20), and severe preeclampsia ( n = 20). Preeclampsia diagnosis/severity followed the American College of Obstetricians and Gynecologists criteria. ONSD was measured by ocular ultrasonography (Voluson S8) 3 mm posterior to the globe in both eyes; the mean of both eyes was analyzed. Measurements were performed contemporaneously by four radiologists and recorded by consensus.

Groups were comparable regarding age, gravidity, parity, and gestational week at measurement (mean gestational age 34.20 ± 0.70 weeks; P > 0.05). Mean ONSD increased stepwise across groups: 4.11 ± 0.21 mm (nonpregnant controls), 4.62 ± 0.19 mm (pregnant controls), 5.71 ± 0.18 mm (preeclampsia), and 5.99 ± 0.20 mm (severe preeclampsia) ( P < 0.001). An ONSD cutoff of 5.15 mm distinguished preeclampsia/severe preeclampsia from the control groups with excellent diagnostic performance (AUC = 1.000; P < 0.001).

ONSD is higher in preeclampsia, especially in severe cases. Ocular ultrasound may help with quick screening and follow-up, but confirmation in larger studies using imaging or invasive ICP standards is needed.