What Is a Lens?

Video Transcript

"I'm Dr. Jim Kirkconnell with Bellevue Eye Care Center here in Nashville, Tennessee. I want to show you what lenses are. This is, we call it a stock lens, it's a minus five lens which is for somebody whose fairly strong near sided. Lenses are composed of resin today, that means it's optical plastic. There are different kinds, those that are more dense are thinner in the middle than this one, thinner on the edge rather than this one. And, then we have some things that are made out of glass, but that's very, very few anymore because glass does shatter. This one shows how it's thinner in the middle, and thicker on the edge for people who are near sided in order to allow light to diverge. This one is thicker in the middle and thinner on the edge for people who are far sided or hyper optic and this one is for someone who is near sided with astigmatism, and there's actually through this area, it is more steep this way, than it is this way, and that's the way we correct for defects of the cornea when you have an eye which is more steeply curved this way, than it is this way."