Blackberries are a rich source of bioactive compounds, notably anthocyanins, vitamin C, and other antioxidants, which have been studied for their potential benefits to eye health. Several in vitro and animal studies suggest that anthocyanins may help protect retinal cells from oxidative stress, a contributing factor in conditions like age-related macular degeneration (AMD) and cataracts. The high vitamin C content in blackberries also supports collagen formation, which is important for the structure of the eye, particularly the cornea and blood vessels within the eye.

However, direct clinical evidence supporting blackberries specifically for improving or maintaining human eye health is limited. Most available research focuses on broader dietary patterns rich in fruits and vegetables, rather than blackberries alone. While the antioxidant properties of blackberries theoretically contribute to eye health, there are currently no large-scale, high-quality human trials demonstrating that blackberry consumption alone has a significant or unique effect on preventing or treating eye diseases.

In summary, the use of blackberries to support the eyes is based on their antioxidant profile and some preliminary laboratory findings, but robust scientific validation in humans remains limited. Therefore, while there is a scientific rationale, the evidence supporting blackberries for eye health is still considered weak (rated 2 out of 5).