Lots More Information
Related HowStuffWorks Articles
- How Corrective Lenses Work
- How Your Eyes Work
- How Light Works
- How the Sun Works
- How Sunburns and Sun Tans Work
- What is 20/20 vision?
- How do sunless-tanning products work?
- What is a "sunburn"?
- Is there a way to make my sunglasses scratch-resistant?
More Great Links
- Corning Museum of Glass
- Plastics.org
- Transitions
- Color Lenses and Photochromics
- Berkeley Lab: Photochromic windows
