Voriconazole is a broad spectrum, triazole antifungal agent used for systemic fungal infections. It has a favourable safety profile and is available in both intravenous and oral forms. The commonest adverse drug reactions with voriconazole are changes in visual perception, namely, increased visual perception (object appearing brighter), subjective blurred vision, changes in colour vision and photophobia (glare or dazzle). This study was to investigate the effects, and their reversibility, of multiple oral doses of voriconazole on a variety of visual tests in healthy male volunteers. Thirty-six volunteers were enrolled in the study who received voriconazole (400mg every 12 hours on day one, then 300mg every 12 hours for 27.5 days). Electroretinography (ERGs) and ophthalmic examinations were carried out at screening and throughout the study period. Fifteen (83.3%) volunteers experienced >1 treatment-related visual adverse events (AEs). No serious AEs were reported. There were reduced scotopic maximal a- and b-wave amplitude, shortened implicit time and decreased oscillatory potential amplitude compared with placebo. Under photopic conditions, the 30-Hz flicker response was significantly reduced too. The study concluded that effects of voriconazole on altered visual perception, ERG, colour vision and static visual field thresholds were non progressive over a treatment period and reversible.