BACKGROUND: A patient with a third cranial nerve (CN III) palsy can be a stress inducing event for an optometrist due to the potentially life-threatening etiologies and infrequency of their presentation. The pathogenesis of a CN III palsy can vary from innocuous to life threatening. Palsy of the third cranial nerve results in an impairment of eye movement and / or pupillary response to light depending on the extent of the palsy. CASE REPORT: This case reviews a recent onset of a complete right oculomotor palsy. Literature of similar cases detail the likelihood of variable causes, and while a diagnostic work-up is indicated based on the risk, the etiology of the palsy in this case was determined to be more benign in nature. CONCLUSION: Large scale population studies in the literature reveal the etiology of a CN III palsy from life-threatening conditions is lower than indicated based on published case reports. However, a complete evaluation of a patient including neuro-imagining is still warranted due to the potential life-threatening complications. Further population studies with increased diversity need to be performed to advance knowledge in this area.