In America and the UK there are anti-drug programmes such as Narcinon, using a regime of exercise, saunas and vitamin B the church claims it has a 75% success rate.
Some Class 2 lenses beat the standard: Avaira, for example, block at least 75% of UV-A radiation and 99% of UV-B radiation, according to the package insert.
They indicate the minimum score on each of the four subject tests for a student who has a 75% chance of earning a grade of C or higher or a 50% chance of earning a B or higher in a typical first-year college course.