Background:Using ultrasound to measure optic nerve sheath diameter(ONSD)is an emerging bedside technique to noninvasively assess intracranial pressure(ICP)in patients with brain injury.This technique is unique among bedside ultrasonography and is often performed by providers who have no formal ultrasound training.We sought to create a low-cost,3D,reusable ONSD model to train neurology,neurosurgery,and critical care providers in measuring ICP.Results:We identified 253 articles,of which 15 were associated with models and 2 with simulation.One gelatin model was reported,upon which we based our initial design.We could not validate the visual findings of this model;however,after constructing multiple beta models,the design most representative of human eye anatomy was a globe made of ballistics gel and either a 3 mm,5 mm,or 7 mmx50 mm 3D-printed optic nerve inserted into a platform composed of ballistics gel,all of which sat inside a 3D-printed skull.This model was used to teach ONSD measurements with ultrasound at a continuing medical education event prior to training on a live human model.Conclusions:A simple 3D ballistic ONSD model allows learners to practice proper hand placement and pressure,basic landmarks,and ONSD measurement prior to operating on a human eye.This model is replicable and sustainable given that the globe and platform are composed of ballistics gel.