Ads
related to: contact lens material chartopticontacts.com has been visited by 10K+ users in the past month
ebay.com has been visited by 1M+ users in the past month
glassesusa.com has been visited by 100K+ users in the past month
The quality of the glasses was outstanding. - Bizrate
Search results
Results from the WOW.Com Content Network
Lenses made of PMMA are called hard lenses. [5] Soft contact lenses were first produced in 1961 by Czech chemical engineer Otto Wichterle using polyhydroxyethylmethacrylate (pHEMA), a material that achieved long-term commercial application. Lenses made of polyacrylamide were introduced in 1971. [5]
Contact lens. A pair of contact lenses, positioned with the concave side facing upward. Putting contacts in and taking them out. One-day disposable contact lenses with blue handling tint in blister-pack packaging. Contact lenses, or simply contacts, are thin lenses placed directly on the surface of the eyes. Contact lenses are ocular prosthetic ...
Oxygen permeability ( OP) is a parameter of a contact lens that expresses the ability of the lens to let oxygen reach the eye by diffusion. In soft contact lenses, it is dependent on the thickness of the lens and the material of the lens, especially concerning the water content. Because of this dependence on thickness, transmissibility level ...
Abbe number. In optics and lens design, the Abbe number, also known as the V-number or constringence of a transparent material, is an approximate measure of the material's dispersion (change of refractive index versus wavelength), with high values of V indicating low dispersion. It is named after Ernst Abbe (1840–1905), the German physicist ...
Many materials have a well-characterized refractive index, but these indices often depend strongly upon the frequency of light, causing optical dispersion. Standard refractive index measurements are taken at the "yellow doublet" sodium D line, with a wavelength (λ) of 589 nanometers . There are also weaker dependencies on temperature, pressure ...
Base curve radius, or simply base curve, abbreviated BCR or BC, is the measure of an important parameter of a lens in optometry. On a spectacle lens, it is the flatter curvature of the front surface. On a contact lens it is the curvature of the back surface and is sometimes referred to as the back central optic radius (abbreviated BCOR ).