The aim of this study was to determine whether there is a difference between the horizontal prism fusion amplitude measured with and without the Bagolini striated glasses (BSG) in 52 young adults. Subjects had a mean age of 21.06 years, 13.5% were male, 30 were exophoric and seven esophoric. Right eye dominance was present in 36 and left eye dominance in 16 subjects. The results showed significantly smaller fusional ranges obtained with BSG during measurements at near fixation. No differences were found with / without BSG at distance. Ocular dominance had no effect. BSG affects results with altered natural viewing conditions.