27 July, 2017
Eyeglasses for farsightedness, also called hyperopia according to Ohio State University Medical Center (OSU), use convex lenses. A convex lens magnifies objects. There are other uses for convex lenses besides vision correction with magnifying glasses, contact lenses and eyeglasses. Scientists, hobby enthusiasts, and sportsmen also use convex lenses.
Convex lenses are thicker in the middle then the edges and concave lenses are thicker at the edges then the middle. As light travels through the lens, it bends either outward or inward, toward the thickest part of the lens. The University of California, San Diego (UCSD) notes that a convex lens magnifies by bending the light into a focal point and helps you see an object that is very far in the distance or very small.
Eye glasses are the most popular kind of convex lenses for vision correction according to OSU. A frame holds two glass or plastic lenses, which are either concave for nearsighted vision or convex for farsighted. Contact lenses that correct for farsighted vision problems are also convex.
Convex lenses are used by scientists. Microscopes have a convex lens and a concave mirror and a flat mirror to magnify small images on a slide. Telescopes use convex lenses. The University of Virginia's Biology Department notes that refracting telescopes use two convex lenses and reflecting telescopes use convex and concave lenses and a flat mirror to magnify.
Cameras have convex lenses that focus an image on film or a sensor in a digital camera. Telescopic rifles have convex lenses that work similarly for scientific telescopes. Binoculars also use convex lenses.
Your eye has a double convex lens which focuses an image on the retina at the back of the eye, similar to how a camera uses a convex lens to focus an image on film.
- lens image by Rog999 from Fotolia.com