Admission optic nerve sheath diameter and optic nerve sheath diameter/eyeball transverse diameter ratio as prognostic markers in stroke

Objectives: Raised intracranial pressure (ICP) is a major determinant of secondary injury in acute stroke. Optic nerve sheath diameter (ONSD), measurable on computed tomography and magnetic resonance imaging, may provide a simple non-invasive surrogate of ICP, but data from Indian stroke populations are limited. Materials and Methods: This retrospective study analyzed 36 adult patients with ischemic or hemorrhagic stroke admitted to a tertiary intensive care unit between March and September 2022. Of 54 eligible patients, 36 had complete imaging suitable for standardized ONSD and eyeball transverse diameter (ETD) measurements and complete outcome data and were included in the final analysis. Bilateral ONSD and ETD were measured from admission neuroimaging, and mean ONSD, maximum ONSD (ONSD_max), ONSD asymmetry, and ONSD/ETD ratio were calculated. Outcomes included intensive care unit (ICU) mortality, decompressive surgery, ventilator days, and ICU stay. Multiple imputation and multivariable regression were used. Results: The mean age was 55.5 ± 17.4 years; 72% were male. Hypertension (58%) and diabetes (44%) were common. Ischemic stroke predominated (72%). Midline shift and herniation were present in 42% and 11%, respectively. ICU mortality occurred in 4 patients (11.1%), and 12 patients (33.3%) underwent decompressive hemicraniectomy. Mean ONSD was 6.59 ± 0.99 mm, ONSD_max 7.12 ± 1.10 mm, and ONSD/ETD ratio 0.290 ± 0.060. Patients who died in the ICU had higher ONSD_max values compared with survivors (median 7.6 mm vs. 7.0 mm). ONSD_max demonstrated better mortality discrimination (area under the curve [AUC] 0.70) than mean ONSD (AUC 0.48). Mean ONSD significantly predicted ventilator duration (b = 0.44 ± 0.18, p = 0.015). ONSD asymmetry and ONSD/ETD ratio showed no independent prognostic value. Conclusion: In this Indian ICU stroke cohort, ONSD_max demonstrated better mortality discrimination than mean ONSD, while mean ONSD predicted duration of mechanical ventilation. These findings highlight ONSD_max as a simple, clinically relevant biomarker of raised ICP, particularly valuable in resource-limited settings.