OBJECTIVE: To determine the influence of the use of central nervous system (CNS) stimulants on visual functions and occurrence of road traffic accidents (RTA) amongst commercial drivers. DESIGN: A cross-sectional study in which two hundred and fifteen consecutive drivers were interviewed and their eyes examined. SETTINGS: Ife Central Local Government Area (LGA) of Osun State, Nigeria. MATERIALS AND METHODS: Out of the estimated 270 commercial drivers registered in the four major parks of the LGA, 215 consecutive drivers participated in the survey. Questionnaires were administered by face – to – face interview and the drivers’ eyes examined by the authors. RESULTS: The prevalence of visual impairment (visual acuity < 6/18) in the better eye without correction was 3.3%, and there was a significant association between uncorrected visual acuity impairment in the better eye and RTA (p = 0.0152). The prevalence of refractive error was 8.4%, but none of these drivers wear corrective glasses. Alcohol consumption is common (57.7%) amongst the drivers, and there was a significant association between alcohol consumption and RTA (p = 0.00124). There was also a significant association between the use of CNS stimulants (kolanut, marijuana and cigarette) and RTA (p = 0.005). CONCLUSION: It was therefore concluded that visual impairment in the better eye, alcohol consumption and the use of other CNS affecting substances contribute to the occurrence of RTA among the drivers.