When.com Web Search

Search results

1. Results From The WOW.Com Content Network

2. Corrective lens - Wikipedia

   en.wikipedia.org/wiki/Corrective_lens

   Aspherics are only [citation needed] used for corrective lenses when, in order to achieve a flatter lens for cosmetic reasons, the lens design deviates from the best-form sphere; this results in degradation of the visual correction, degradation which can, in some part, be compensated for by an aspheric design. The same is true for atoric and bi ...

3. Astigmatism (optical systems) - Wikipedia

   en.wikipedia.org/wiki/Astigmatism_(optical_systems)

   Astigmatism causes difficulties in seeing fine detail. Astigmatism can be often corrected by glasses with a lens that has different radii of curvature in different planes (a cylindrical lens), contact lenses, or refractive surgery. [5] Astigmatism is quite common. Studies have shown that about one in three people suffers from it.

4. Eyeglass prescription - Wikipedia

   en.wikipedia.org/wiki/Eyeglass_prescription

   A spherical lens has the same curvature in every direction perpendicular to the optical axis. Spherical lenses are adequate correction when a person has no astigmatism. To correct for astigmatism, the "cylinder" and "axis" components specify how a particular lens is different from a lens composed of purely spherical surfaces.

5. Toric lens - Wikipedia

   en.wikipedia.org/wiki/Toric_lens

   One of the lens surfaces is shaped like a "cap" from a torus (see figure at right), and the other one is usually spherical. Such a lens behaves like a combination of a spherical lens and a cylindrical lens. Toric lenses are used primarily in eyeglasses, contact lenses and intraocular lenses to correct astigmatism.

6. Adjustable-focus eyeglasses - Wikipedia

   en.wikipedia.org/wiki/Adjustable-focus_eyeglasses

   Adjustable focus lenses, like single-focus lenses, also reduce image-jump and spatial distortion in the field of view associated with traditional multi-focal lenses. Additionally, the ideal near-vision correction can be achieved with precision, because the variable lenses emulate the focusing action of the youthful (non-presbyopic) eye.

7. Why astigmatism causes blurry vision, especially at night - AOL

   www.aol.com/news/why-astigmatism-causes-blurry...

   Astigmatism, a disorder that affects how the eyes focus light, can be exacerbated at night. Blurry vision and headaches are symptoms of astigmatism. Why astigmatism causes blurry vision ...