Updated December 04, 2014.
Written or reviewed by a board-certified physician. See About.com's Medical Review Board.
Polycarbonate lenses are impact-resistant, providing eye protection. Polycarbonate lenses are often prescribed by eye doctors for people who participate in certain sports or have jobs that carry the risk of broken eyeglasses. Polycarbonate lenses also block 100 percent of the sun's UV rays. Polycarbonate lenses are the most popular lenses made today.
Regular glass or plastic lenses carry the risk of shattering in the case of trauma or an accident. A shattered lens can injure the eye. If a polycarbonate lens is hit with force, it will not shatter, but rather mold in and remain together. Polycarbonate is the same plastic used in bulletproof windows and is 10 times more impact-resistant than glass or regular plastic.
Polycarbonate lenses can also cause chromatic aberration. Chromatic aberration occurs when the eye or an optical system fails to focus light of different colors or wavelengths at the same point, causing vision to be less sharp or distorted around certain objects.
Even though polycarbonate lenses are shatter-proof, they are easily scratched. However, scratch-resistant coatings can be added to help prevent scratching.
Source:
The University of Michigan Kellogg Eye Center. "Preventing Eye Injuries." 26 Jun 2007.
Written or reviewed by a board-certified physician. See About.com's Medical Review Board.
Polycarbonate lenses are impact-resistant, providing eye protection. Polycarbonate lenses are often prescribed by eye doctors for people who participate in certain sports or have jobs that carry the risk of broken eyeglasses. Polycarbonate lenses also block 100 percent of the sun's UV rays. Polycarbonate lenses are the most popular lenses made today.
What makes polycarbonate lenses so safe?
Polycarbonate is the most impact-resistant lens available.Regular glass or plastic lenses carry the risk of shattering in the case of trauma or an accident. A shattered lens can injure the eye. If a polycarbonate lens is hit with force, it will not shatter, but rather mold in and remain together. Polycarbonate is the same plastic used in bulletproof windows and is 10 times more impact-resistant than glass or regular plastic.
Who needs polycarbonate lenses?
Polycarbonate lens material is lightweight and thin, making it cosmetically appealing to many people. These lenses are especially recommended for the following people:- Children: Since polycarbonate lenses are shatter-proof, a child's eyes won't be damaged by shards of flying glass or plastic if the glasses are hit hard by a ball or a bat.
- Monocular patients: People who only have one eye or who have decreased vision or blindness in one eye -- called monocular vision -- should wear a polycarbonate lens. Because monocular patients are using only one eye for vision, it is imperative that they do everything they can to protect their best-seeing eye.
- Industrial workers: People involved in occupations that have a high risk of injury must take extra precautions to protect their eyes.
- Athletes: Those participating in high-impact sports should regularly wear safety lenses to protect their eyes from injury.
What are the disadvantages of polycarbonate lenses?
Although fine for most people, a small percentage of the population complain that they do not see as clearly through polycarbonate lenses. Polycarbonate material is prone to expand and contract in extreme temperatures, which can lead to distorted vision.Polycarbonate lenses can also cause chromatic aberration. Chromatic aberration occurs when the eye or an optical system fails to focus light of different colors or wavelengths at the same point, causing vision to be less sharp or distorted around certain objects.
Even though polycarbonate lenses are shatter-proof, they are easily scratched. However, scratch-resistant coatings can be added to help prevent scratching.
Source:
The University of Michigan Kellogg Eye Center. "Preventing Eye Injuries." 26 Jun 2007.