Even for pathological patients, the solution is to reset their eye with e.g LASIK and to prevent growth via bilberry. It's non-prescription is one instance of the universal established deep mediocrity
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6296196/
I don't know but you have to understand that in general, extracts achieve effective concentrations that are impossible to achieve naturally. Moreover, a pill is easy to take consistently in the morning, while eating a bunch of billberries every morning is a chore. Consistency is key for the goal.
I guess eating bilberries is better than nothing, you'd have to study the extract to infer how many bilberries per pill it represent.