I often work on projects on my Mac until the wee hours and sometimes fall asleep doing it. Several times I have ended up on top of these glasses and thought surely they would be hopelessly broken. After a year and a half of that, the only damage I have done is a slight bend downward of one hinge. That, folks, is toughness. The optics are even and clear and do not cause eye strain even after many hours of use. The bamboo is quite nice and weathers well even when exposed to moisture. These glasses are just plain excellent. Thanks.