- HEMA by Xavier Miller
Transparent hydrophilic plastic used in the manufacture of soft contact lenses. It stands for 2-hydroxyethyl methacrylate. See index of refraction; contact lens.
- astigmatism by Zoe Bush
Lack of symmetry in the curvature of the cornea or, rarely, the lens of the eye. The unequal curvatures spread light rays, preventing them from being sharply focused at a point on the retina, causing blurring of part of the image. The effect of astigmatism can also be produced by ...
- contact by Cameron Hanson
... that makes the junctionc. the part of an electrical device to which such connections are made any person who has been exposed to a contagious disease an informal name for contact lens of or relating to irritation or inflammation of the skin caused by touching the causative agent
- eyeglasses by Bryan Ramsey
... (lighter and more shatterproof than glass but easily scratched). Sunglass lenses are tinted to reduce glare and often treated to reduce ultraviolet light exposure. See also. contact lens.
- optics by Lauren Riley
... of the information content of an image formed by coherent (one-wavelength) optical systems. The study of optics has led to the development of devices such as eyeglasses and contact lenses, telescopes, microscopes, cameras, binoculars, lasers, and optical fibres ( see fibre optics).