Ad
related to: transpose cylinder in glassesglassesusa.com has been visited by 100K+ users in the past month
Search results
Results From The WOW.Com Content Network
Cylindrical lenses. A cylindrical lens is a lens which focuses light into a line instead of a point as a spherical lens would. The curved face or faces of a cylindrical lens are sections of a cylinder, and focus the image passing through it into a line parallel to intersection of the surface of the lens and a plane tangent to it along the cylinder's axis.
A torus results when a circle with radius r rotates around an axis lying in the same plane as the circle (here the z axis) at a distance R from the centre of the circle.. A torus is the surface of revolution resulting when a circle with radius r rotates around an axis lying within the same plane as the circle, at a distance R from the circle's centre (see figure at right).
Cylinder blown sheet is a type of hand-blown window glass. It is created with a similar process to broad sheet, but with the use of larger cylinders. In this manufacturing process glass is blown into a cylindrical shape by a glass blower. The ends of the cylinder are cut off and a cut is made down the side of the cylinder.
The cylinder power is refined by superimposing the 0.50JCC over the correcting cylinder axis in the trial frames. The patient is asked to indicate whether it is clearer with or without the lens. Dioptric changes are then made in 0.25 increments in order refine cylindrical correction.
The structure of glasses differs from the structure of liquids just above the glass transition temperature T g which is revealed by the XRD analysis [10] and high-precision measurements of third- and fifth-order non-linear dielectric susceptibilities. [11] Glasses are generally characterised by a higher degree of connectivity compared liquids. [12]
Using a phoropter to determine a prescription for eyeglasses. An eyeglass prescription is an order written by an eyewear prescriber, such as an optometrist, that specifies the value of all parameters the prescriber has deemed necessary to construct and/or dispense corrective lenses appropriate for a patient.
Machine drawn cylinder sheet was the first mechanical method for "drawing" window glass. Cylinders of glass 40 feet (12 m) high are drawn vertically from a circular tank. The glass is then annealed and cut into 7 to 10 foot (2 to 3 m) cylinders. These are cut lengthways, reheated, and flattened.
A phoropter measurement of a patient reads −8.00 D sphere and −5.25 D cylinder with an axis of 85° for one eye (the notation for which is typically written as −8 −5.25×85). The phoropter measurement is made at a common vertex distance of 12 mm from the eye.