 Phil Brady with Dr. Kopstein from K2 Vision RLE. Doc, is it true 50% of Americans have their lenses replaced by the time they're 75? That's exactly right. As we near 50, our eye's natural lens starts to become dysfunctional. If you've now added readers to your need for glasses and contacts, it's a sign the quality and function of your natural lens is fading, and it's a steady decline towards cataracts.