Sunglass Glossary
Confused about the various terms related to the sunglass industry? Want to knowwhat all these buzzwords really mean? Check out the definitions below:
1. Abbe Value – Abbe Value is the index to measure chromatic aberration in lenses. It is also known as the V-number or constringence of a transparent material. Abbe Value of your sunglasses can measure the colour fringes above and below or to the left and right of a high contrast object.
2. Anti-Reflective coating – Anti-reflective coatings improve the quality and the value of your lenses by reducing disturbing reflections. Anti-Reflective coating on your sunglasses make you experience the crisp and clear natural vision and it is not possible with uncoated lenses.
3.ANSI Z87.1 Standards - This is the Safety standards that must be met for the glasses considered as the safety glasses.
4.Astigmatism – A misshape of the eye, where vision is blurred by an irregularly shaped cornea. Instead of being sphere in shape, cornea becomes ellipsoidal (like an egg). Astigmatism reduces the cornea's ability to focus light.
5.Axis – Axis indicates the placement in degrees of the astigmatic lens.
6.Backside Coating – Backside coating is required to protect the sunglasses lenses from scratching.
7.Ballistic – Ballistic sunglasses are shatter-resistant, rugged and exceeds ANSI Z87.1 safety and military MIL-STD-662 standards.
8.Bifocal – Bifocal lenses are those, which contains two regions with two distinct optical powers. Bifocal glasses are commonly prescribed to people with presbyopia who also require a correction for myopia, hypermetropia, and astigmatism.
9.Bridge size – Bridge size is the width between the lenses on a sunglass frame. Manufacturers typically measure this width at the widest point between the two lenses.
10.Blue Blocker – Blue Blocker lenses are those, which guards the blue light.
11.Blue Blur – Blue Blur is a condition of unclear vision. It happens when the blue light waves are short and scattered easily in the visible light spectrum. A blue blocker lens is recommended as a remedy of this aversion in visual acuity.
12.Clip-on – Clip-on is a small device fitted with sunglass lenses that hooks onto your prescription eyeglasses. Clip-ons are handy, convenient and easy to use.
13.Colour-Coated Lenses – Lenses that have a colour coating applied to the outside of the lens.
14.Contrast – Contrast is the difference in brightness between the light and dark parts of an image. A higher contrast lens provides greater visual acuity.
15.Cornea – Cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber, controlling most of an eye's optical power.
16.CR-39 – CR-39 is a lightweight plastic lens material that is easily tinted to just about any colour. Standard Plastic CR-39 Lenses are much lighter and less breakable than glass lenses.
17.Cylinder – Cylinder lenses are prescribed for a person suffering from astigmatism.. If there is no cylinder value on your prescription, you do not have astigmatism.
18.Diopter – Diopter is the unit of lens's refractive power. It is equal to the reciprocal of the lens's focus length in meters.
19.Drive Wear – A type of Transition Lens that transitions behind the wind shield of a car. Drive wear lens is specifically designed for driving. The lens shade varies depending on exterior lighting conditions, but never turn completely clear.
20.EN1836:2005 - It is a standard for health and safety applied by European Union Countries to check that sunglasses conform to the health and safety requirements laid down in The European Directive 89/686/EEC.
21.Eye size – Eye size determines the horizontal measurement of the lens on any frame at its widest part. This is measured in millimetres.
22.G 15 – G 15 is green-grey coloured lens, that is a popular general purpose lens.
23.Glass – Glass lenses are scratch resistant and easily tinted, but are double the weight of plastic lenses. Glass lenses have excellent optical qualities and can have a refractive index as high as 1.90.
23.Grilamid nylon frames – Grilamid nylon frames is a rugged, resilient, strong but flexible, lightweight material used in frames that retains its shape and withstands extreme temperatures.
24.High Index 1.56 - 1.56 lenses are 25% thinner than plastic and comparable to other high index lenses, giving the wearers slimmer glasses and a wider choice of frames. A flattened, aspheric design makes 1.56 high index lenses up to 50% flatter than regular plastic and 35% flatter than spherical high index lenses, so lenses bulge less from the frame and maintain clear optics.
25.High index 1.67 – High index 1.67 lens is a thin and light weight lens, designed with a built in UV protection. It is thinner than plastic and polycarbonate lens.
26.High Index 1.70 - Hi-Index 1.70 lenses have built-in UV protection and automatically anti-reflective coated. These are available in single vision spherical and single vision aspherical, the lens design offers a clear, stable and natural viewing experience.
27.High Index 1.74 – Hi-Index 1.74 lenses are the thinnest, flattest, and most appealing lens ever developed. It deserves the best of all technologies including the most advanced anti-reflective (AR) lens treatment.
28.Hi Index Glass Lenses – Hi Index Glass Lenses are available in a wide range. 1.6 high index lenses can be finished to a 1.5mm centre in minus prescriptions and still meet United States FDA impact resistance standards. These high quality lenses are also available in 1.7, 1.8 and 1.9 indexes outside the United States.
29.Hyperopia – Hyperopia is the disease which makes one unable to focus on near objects. But such people can have the distant vision.
30.Infra-red (IR) Radiation – Radiant energy not normally considered harmful but wide exposure to it can cause a burning of the unprotected eyes, especially in case of contact lens wearers. This radiation is called IR radiation. Be sure your sunglasses stop IR radiation.
31.Macular degeneration – Macular degeneration is a disease that causes deterioration of the central portion of the retina known as the macula. Continuous deterioration of macula leads to blindness. Macular degeneration often results in loss of central vision, leading to the inability to see fine details, to read or to recognize faces distinctly.
32.Melanin polarized lenses – Melanin polarized lenses are highly protective against UV radiation, blue light and glare. These lenses are well suited to outdoor enthusiasts.
33.Mirrored coating – Mirrored coating is a kind of surface coating, which is applied to the outside of a lens that absorbs 10 to 60 percent more light than uncoated lenses. Mirrored coating lenses appear darker and add additional glare protection.
34.Myopia -Myopia is a disease of eyes and people affected with myopia can see nearby objects clearly but distant objects appear blurred to their vision.
35.Nose pad – The pads mounted to eye wear on either side of the nose that support the frames to fit properly on the nose.
36.Oakley Plutonite – Oakley's patented XYZ Optics maintains visual clarity at all angles of view. Oakley premium eye wear surpasses the protection requirements for high-mass impact as well as high-velocity impact, as defined by The American National Standards Institute (ANSI).
37.Ocular – Anything related to the eye is known as Ocular
38.O. D. & O. S. – O.D. is the right eye and O.S. is the left eye.
39.Pentax - Pentax lenses are extremely thin and light. It has used the highest index of refraction at 1.67. High index no longer means thick, chunky lenses that can only be glazed into heavy frames. 1.67 lenses are up to 60% thinner than regular plastic lenses.
40.Photochromic – Photochromic lenses automatically turn dark in bright light and lighten indoors. The lenses are activated in exposure to the ultraviolet light and will not darken behind the protection of your windshield. Such lenses do not get as dark as normal sunglasses nor do they get perfectly clear when they lighten.
41.Polarized lenses – Polarized lenses are those, which filtered the amount of reflected light that enters the eye. The effect of the polarized lenses on the reflected glare is most noticeable on water, snow, or concrete and asphalt surfaces.
42. Polycarbonate – Polycarbonate lenses are lightweight and have built in UV protection. It is highly recommended for children, sports. Polycarbonate lenses are well fitted with the rimless frames also. Originally used for industrial safety glasses, polycarbonate lenses now used for children, sports wearers, or anyone requesting greater resistance in their lenses.
43.Presbyopia – Presbyopia is a disease leading to the inability to focus difference between distance vision and near. It is mostly observed during reading from paper or digital screen.
44.Prism – Prism is a wedge-shaped lens which is thicker on one edge. Prism lens is used to measure an eye misalignment and to treat a binocular dysfunction. A prism is sometimes added to glasses in order to improve eyesight due to an eye misalignment or visual field loss
45.Progressive lenses – Progressive lenses are no-line bifocals. There is no discernible line between the regions of optical power on the corrective lens with progressive lenses.
46.Pupillary Distance (PD) or Pupil Distance – Pupillary distance (PD) is the distance (measured in mm) between the center of the pupils of eyes when looking far away in the distance.
47.Round-Seg Bifocal - Uses a round reading section for the bifocal lens that is put on the back of the lens rather than the front, putting the lens closer to the eye for an expanded reading area.
48.Scratch resistant coating – It is a kind of coating on the lenses that makes it prone to scratching.
49.Sphere – The sphere number of your lens denotes the strength of the lens in diopters.
50.Temple length – The length of the arm of the frame running from the hinge to the end that wraps behind your is called temple length. It is measured in millimetres.
51.Transitions Lenses – Transition lenses are a kind of Photochromic lenses, which transitions from clear to dark in the presence of ultraviolet light and block 100% of harmful UV rays. Innovative photochromic technologies have produced unparalleled lens performance in nearly every lens design and material, including shatter-resistant lenses, bifocals, trifocals, progressives, and standard and high index materials.
52.Trifocals – Trifocals are corrective eye wear lenses containing regions with three distinct optical powers. The three standard regions are distance at the top, intermediate in the middle and reading towards the bottom of the lens.
53.Trivex lenses -Trivex lens material lets you prescribe a single, thin lens with the qualities of many. Trivex lens combines the key lens attributes while offering superior optics. Only the finest lenses provide such tri-performance — superior optics, impact resistance and ultra light weight.
54.Ultraviolet (UV) radiation – Invisible to the eye, prolonged exposure to solar UV radiation may result in acute and chronic health effects to the eyes.
55.UV Filter – A lens coating, either made on the lens or embedded in the lens, that filters out the UV radiation.
56.Visible Light – Visible light is part of the light spectrum which the eye recognizes as colour. The eye can be protected from excessive amounts of visible light by covering it with protective eye wear.
57.Wrap Frame – Wrap frame are those which wraps around your face. Wrap around sun glasses are highly popular both among the old and young.
