Pupil assessment can provide critical information on the integrity of early afferent visual pathways， and measuring the change in pupil diameter and detecting pupillary light reflex are indispensable test items in neurosurgery. Objectivebased infrared pupillometry is now becoming more and more common in quantitative dynamic pupil assessment and can provide more comprehensive pupillary light reflex （PLR） parameters and detect subtle visual conduction defects， thereby showing great potential in the diagnosis， monitoring， and treatment of traumatic brain injury. Mild traumatic brain injury （MTBI） is the most common type of brain injury， and no substantial pathological changes can be observed on neuroimaging in most cases， leading to the difficulty in clinical diagnosis. Studies have shown a dynamic slow-down of the pupillary system in patients with MTBI， with reductions in mean pupillary constriction velocity and mean pupillary dilation velocity observed in the acute， subacute， and chronic stages. This article briefly introduces the PLR pathway， summarizes the application of pupillometry techniques in patients with MTBI in recent years， and discusses the value of PLR parameters as the potential visual biomarkers for the diagnosis of MTBI and the influence of photosensitivity and refractive error on its accuracy.