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a refractive power of a lens is expressed in diopter D, a surface refractive power at the surface of the lens is defined by a curvature .rho. of the surface expressed in m.sup.-1 and a refractive index n of a lens material.
Bifocals.Traditional bifocals have a clearly defined zone in the top half of the lens for distance vision and a zone for near vision in the bottom half of the lens. The zones are separated by a noticeable line. Trifocals.These lenses have three different zones for seeing at varying distances...
and a second base curve lower than the first base curve When a predetermined lens having a base curve is defined as an index spectacle lens, a prism action received by the indexing spectacle lens on the prism action received by the initial lens in each line of sight passing through the cen...
56b are confined. This construction may be used to provide a focus adjustment for the crystalline humor or the lens defined thereby. The lens portion defined by the construction of FIG. 17 may incorporate a Fresnel structure as shown in FIG. 18. Specifically, both outer transparent plates 55...
More Commonly Misspelled Words Popular in Wordplay See All More Words with Remarkable Origins 8 Words for Lesser-Known Musical Instruments Birds Say the Darndest Things 10 Scrabble Words Without Any Vowels 12 More Bird Names that Sound Like Insults (and Sometimes Are) ...
1.An optical element, comprising:a base material consisting of a lens; anda surface layer formed on at least one of the surfaces of the lens;wherein a reflectance of a surface of the formed layer for all light rays in a wavelength region of 280 nm to 315 nm and in a wavelength region...
Method for making a plastic lens is provided. More particularly, a method for applying alternating periods of ultraviolet light to a lens forming composition is described. The lens forming composition
(66-3) of semi-finished glasses lens products (10, 12) of a base material with a third average refractive index (nd3) other than the first index of average refraction (nd1) and of the second index of average refraction (nd2), presenting the third series (66-3) in pairs of different ...
(α, the β) function is in the wearer with determining under conditions of having on the eyeglass; And the first acuity index AcuityCriterion1, the first acuity index meets claimed below: AcuityCriterion1 ≥1340D2.Deg2, and wherein: AcuityCriterion1 is defined as the combination of PPO (...