SPH(or Sphere) indicates the eyeglass prescription power, or how strong your lenses need to be to correct your vision. CYL (or Cylinder) indicates astigmatism, a condition where the cornea is irregularly shaped causing blurred or distorted vision. It also tells the lens strength needed to fix it. AXIS describes the degree and direction of your astigmatism.
lens [lenz] 1. a piece of glass or other transparent material so shaped as to converge or scatter light rays. See also glasses. 2. the transparent, biconvex body separating the posterior chamber and the vitreous body of the eye; it refracts (bends) light rays so that they are focused on the retina. Called also crystalline lens. In order for the eye to ...
Understanding Prism in Lenses Page 2 DRAFT – D. Meister, 18 February 2014 Figure 2. A prismatic effect is obtained at the center of an optical lens by producing a difference in edge thickness, either by grinding the back
Before the lens undergoes further grinding, the lens must be blocked, or mounted, to begin the process. Blocking involves mounting lenses onto a convex or concave surface (inverse of the tool being used) with pitch or wax. A lens can be blocked individually (Figure 3a), but more often, many lenses with the same radii are mounted on one surface
Eye care professionals use prism correction as a component of some eyeglass prescriptions.A lens which includes some amount of prism correction will displace the viewed image horizontally, vertically, or a combination of both directions. The most common application for this is the treatment of strabismus.By moving the image in front of the deviated eye, double vision can be avoided and ...
Nov 27, 2016· Traditional vs. Digital Eyeglass Lenses. High-definition, or digital lenses, have been described as the most important improvement in prescription eyewear in the last 100 years. The improvement wearers see in moving from traditional lenses to digital lenses has been compared to the difference between a tube television and a new high-definition ...
Plano lenses are eyeglass lenses that provide no vision correction. They are in widespread use as protective equipment or safety spectacles designed to protect against eye injuries caused by flying dust, dirt, metal, wood chips, and other particles. They are also used in PPE meant to protect against liquid chemical splashes and harmful vapors.
What Are Lenticular Eyeglass Lenses? i Thinkstock Images/Comstock/Getty Images. Technology using lenticular lenses has persisted for over a century. The use of these lenses in print means that a surface has many magnified lenses, allowing the image to be magnified differently depending on viewing location, as with a hologram. Recently, this ...
Jun 06, 2013· Grinding: The trace is loaded into the edger and the lens is placed inside. The machine grinds the lens into the correct shape. For more information on prescription eyewear, visit Perfect Glasses ...
High index eyeglass lenses refer to one of several different kinds of plastic lens material. Eyeglass lenses all have a definite "index", which ranges from 1.56 to 1.74. For strong prescription, the higher the index, the thinner the lens; for weak prescriptions, a low index lens will be no thicker than high index eyeglass lenses.
Aug 11, 2019· Polarized Lenses: A colored form of lens that reduces glare of off flat surfaces such as wet roads. The best choice for sunglasses. There are so many different types of eyeglass lenses that, with a little information, it is easy for nearly everyone who wears glasses to get just the right thing to fit their prescription and lifestyle needs.
Progressive lenses, also called multifocal lenses, progressive addition lenses (PAL), varifocal lenses, progressive power lenses, graduated prescription lenses, or progressive spectacle lenses are corrective lenses used in eyeglasses to correct presbyopia and other disorders of accommodation.They are characterised by a gradient of increasing lens power, added to the wearer's correction for the ...
Lens definition is - a piece of transparent material (such as glass) that has two opposite regular surfaces either both curved or one curved and the other plane and that is used either singly or combined in an optical instrument for forming an image by focusing rays of light. How to use lens in a sentence.
An aspheric lens design gives several advantages to eyeglass lenses. An aspheric lens has flatter peripheral curvatures than a regular spherical lens. This reduces the amount a lens may bulge out of an eyeglass frame, reducing magnification of the eyes, which improves cosmetic appearance.
We are a lens replacement service for your eyeglasses and sunglasses. Specify your lens options with our easy to use order tool, so we know exactly what you want. We offer clear prescription lenses, prescription sunglasses lenses, prescription transition lenses, reading lenses, and prescription computer lenses (blue light blocking lenses). We ...
May 11, 2015· Different Types of High Definition Eyeglass Lenses. High definition lenses are fully customized to your frame style, prescription and lens fitting measurements. Currently many brands of these lenses are available in the market with high quality and durability. Here is the list of types of high definition lenses for your eyeglasses.
Now that's HIGH DEFINITION!!! By grinding the prescription using "point to point" backside Surfacing technology this lens also gives less "swim" effect and less distortion in your periphery. Lenses Are available in plastic, polycarbonate, 1.67 super thin hi- index, and transition materials.
WebMD explains different types of eyeglass lenses and lens coatings, along with tips for caring for your spectacles.
Feb 13, 2014· Lens Material or Lens Index. The lens index refers to the "index of refraction," or how much the lens bends the light that enters it. This ensures that the light is focused properly onto the retina, helping you to see clearly when wearing your glasses. In general, the higher the index, the thinner the lens.
Every prescription lens purchase will come with free Edge Polishing, Ultra Violet Protection, and Scratch Resistance. There are numerous additional options available for your eyeglass lenses; this is a basic list of the most popular lens styles and materials.
These lenses are generally used for plus (hyperopic) corrections at about 12 diopters or higher. A similar sort of eyeglass lens is the myodisc, sometimes termed a minus lenticular lens, used for very high negative corrections. More aesthetic aspheric lens designs are sometimes fitted.
Jun 03, 2008· The optometrist at Costco really pushed their high index lens along with another option that makes the edges of the lens even thinner.. I asked if this affected peripheral vision and she insisted it did not, so I went ahead and got that as well. However, after receiving the glasses it turns out that there is obvious distortion on the edges..
corrected by a lens with cylinder power in a certain direction. Asymmetrical Design – A lens design that has contour line patterns positioned differently into the nasal and temporal area to produce a right and left lens design. This is eye specific so the lens can not be rotated to make a right or left lens.
Digital progressives lenses, or high-definition lenses, are lenses in eyeglasses that provide sharper vision than regular progressive lenses. Advances in lens manufacturing allow digital progressives to correct a patient's vision while reducing glare when driving at night and providing sharper vision in all lighting conditions, according to All About Vision.
Oct 16, 2017· Plastic or glass lenses? Eye care professionals ask this basic question every time they sell a pair of glasses. Choose glasses that are sturdy, attractive, shatter-resistant, comfortable – and easy to wear. The following holds true for both materials: Choosing the most suitable one hinges on individual factors such as visual acuity and personal taste.
"Digital lenses are the new standard for your eyeglasses," explains Matthew Alpert, O.D., board member and chairman of optometric innovation at VSP Global. While most traditional lenses are made using a dated, abrasive grinding process, digital lenses are manufactured using …
May 05, 2010· It can be helpful to think of very basic lens forms in terms of prisms. Recall, as light passes through a prism it is refracted toward the prism base. Minus lenses therefore resemble two prisms apex to apex spreading light rays outward as they pass through the lens, while plus lenses resemble two prisms base […]
Polishing & Grinding Services . United Lens Company employs the latest technology and techniques from high speed double side polishing, single side precision polishing, cylindrical and spherical polishing for all of your custom substrates. ULC grinds, polishes, and finishes optics with consistent and unsurpassed accuracy.
We continue our specialty today, where any customer can bring us their new or used eyeglass frames and we carefully and accurately insert new lenses into the frame. Over 300,000 pairs strong, and we are still the leader in eyeglass lens replacement. See below for some guides on frame limitations.
Jun 02, 2007· At Visions of Canada we take the utmost care in every detail of making eyeglasses. Here we are grinding down the edges making them smoother and the lenses thinner. For more information, or to ...
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