Our Knockaround Rx program offers three lenses: CR-39 lenses, Polycarbonate lenses, and High-Index 1.67 lenses for people with higher strength prescriptions.
CR-39 lenses are plastic lenses recommended for light prescriptions, up to about +/-1.75. CR-39 lenses are lighter and less breakable than glass lenses but more budget-friendly than polycarbonate or high-index lenses.
Polycarbonate lenses are 30% thinner and lighter than CR-39 and recommended for people with prescriptions ranging from +/- 2.00 to +/-4.00. Polycarbonate lenses are also recommended for children and anyone who has an active lifestyle, due to its impact-resistance.
For people with strong prescriptions, High-Index 1.67 lenses are a thinner lens option that helps reduce the distortion of your eyes that people see when they look at you through your glasses. This lens material is recommended for people with prescriptions up to +/- 9.00.