A picture of ocular B-scan that was taken during data collection. Markers were edited and colored for clarity; they did not reflect real-time measurement. Measurement was taken 3 mm behind the globe (the distance between white crosses). ONSD external to dura mater/external ONSD (the distance between red crosses). ONSD internal to dura mater/internal ONSD (the distance between blue crosses). Optic nerve diameter (the distance between orange crosses). ONSD: optic nerve sheath diameter.