The benefit to vision from these nuts is to increase the level of lutein. It is an antioxidant that protects the retina of the eye from ultraviolet radiation and age-related damage. It is also found in carrots, cabbage and spinach, but in lower doses.

Scientists from the American Tufts University monitored 36 healthy people aged 40-70 years for 12 weeks, half of whom added pistachios to their diet daily. The nuts in their portions contained 1.6 mg of lutein. In this group, after six weeks, a significant increase in the density of macular pigment, which protects the eyes from ultraviolet rays, was recorded. This effect persisted until the end of the project.

The study, funded by American pistachio growers, was published in the Journal of Nutrition.