There are numerous studies involving primarily patients with traumatic brain injury in whom visual axis imaging of the ONSD (cutoff range of 4.8-5.9 mm) has been shown to correlate with increased ICP, defined as a pressure ≥ 20 mm Hg., Nonetheless, this approach can be technically challenging, and some investigators have questioned whether this view actually identifies the optic nerve or whether this image represents an artifact, possibly a shadow cast by the lamina cribrosa, the optic disc, or the optic nerve sheath itself. The lateral approach to obtain a coronal view of the optic nerve has historically been used by ophthalmologists. Using this technique with an endocavitary probe, the average ONSD was 3.4 mm (95% CI, 3.18-3.61 mm) in a study of 27 healthy subjects, which is similar to measurements obtained at autopsy. The coronal view in the patient was obtained by placing a linear probe (SonoSite, Inc.; 13-6 MHz, depth of 3.7 cm) oriented vertically with the indicator cephalad and positioned at the lateral canthus. At the point that the optic nerve appeared circular (as opposed to oval, which would represent an oblique cut), the ONSD was measured medial to lateral, outer edge to outer edge, as seen in Figures 1 and 3. We report the patient having an ONSD of 4.3 mm prior to EVD replacement, which improved to 3.3 mm within 15 hours after the procedure, suggesting that the coronal view of the ONSD is time sensitive to changes in ICP. A coronal axis measurement of the ONSD using an infraorbital approach has been described. Measurements of the ONSD in healthy volunteers (n = 42) using this technique were similar to measurements made in the visual axis; however, the images were obtained in less time (200 s vs 152 s; P < .05).