Ads
related to: corrective lens material density
Search results
Results from the WOW.Com Content Network
Density: 2.56 g/cm³ (the heaviest corrective lens material in common use, today) UV cutoff: 320 nm [permanent dead link] Glass lenses have become less common owing to the danger of shattering and their relatively high weight compared to CR-39 plastic lenses.
Corrective lens. A corrective lens is a lens worn in front of the eye, mainly used to treat myopia, hyperopia, astigmatism, and presbyopia. The goal is to bring vision up to 20/20 vision or as close to this as possible. Glasses or "spectacles" are corrective lenses worn on the face a short distance in front of the eye.
In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium. The refractive index determines how much the path of light is bent, or refracted, when entering a material.
A piece of CR-39 manufactured for radiation detection. Poly (allyl diglycol carbonate) (PADC) is a plastic commonly used in the manufacture of eyeglass lenses alongside the material PMMA ( polymethyl methacrylate ). The monomer is allyl diglycol carbonate (ADC). The term CR-39 technically refers to the ADC monomer, but is more commonly used to ...
List of refractive indices. 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 .
FDA classification of soft contact lens materials; FDA lens group Adopted name Transmissibility level (Dk x10-11) Water content Chemical composition I non-ionic low water content: galyfilcon A 60 47% – lotrafilcon A 140 24% DMA, siloxane, TRIS: lotrafilcon B 110 33% polymacon: 7.5 36% HEMA: tetrafilcon 9.0 43.5% HEMA, MMA, NVP: II non-ionic