A defect of this attention or of a lens in result of that the rays produced from one-point are not brought to just one focus hence causing imperfect pictures or indistinctness of sight
- (ophthalmology) weakened vision resulting typically from irregular conformation for the cornea; common in nearsighted men and women
- (optics) problem in an optical system in which light rays from an individual point are not able to converge in a single focus
- A defect of eye or of a lens, in consequence of that the rays based on one point aren't taken to one focal point, therefore causing imperfect photos or indistinctness of eyesight.
A common as a type of visual disability for which section of a graphic is blurred as a result of an irregularity when you look at the dome-shaped curvature associated with forward surface of attention, the cornea. With astigmatism, light rays going into the eye aren't uniformly dedicated to the retina. The end result is blurred sight at all distances. Considerable astigmatism may cause problems, eye strain, and seriously blurry vision. Astigmatism is normally not recognized during routine attention testing in schools. It might coexist with other refractive mistakes such as nearsightedness and farsightedness. Astigmatism is fixed with somewhat cylindrical lenses having higher light-bending energy within one way than the various other. Usage of these contacts elongates items in one way and shortens all of them within the other, just like looking into a distorting wavy mirror.
1849, created because of the Rev. William Whewell (1794-1866), English polymath, from Greek a- "without" (see a- (3)) + stigmatos genitive of stigma "a mark, area, puncture" (see stick (v.)).
(n.) A defect associated with eye or of a lens, in consequence of that the rays based on one point are not brought to just one center point, therefore causing imperfect photos or indistinctness of vision.
These anastigmatic lenses, which are manufactured up to X 40, are chromatically and spherically corrected, and for a middle diaphragm the errors of lateral pencils, distortion, astigmatism and coma are eliminated.