Glossary of Optical Terms |
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| • ABOC Certification • Add (or add power) • Anti-Reflective Coating • Anti-Scratch Coating • ANSI Z87.1 Standards • Astigmatism • Axis • Base • Base Curve • Bridge Size • CR-39 (plastic) • Cylinder • Day and Night (Photochromatic Lenses) • Diopter • Eye size • Flat Light • Frame Measurements • G 15 • Glass • Grilamid Nylon Frames • High index 1.66 • Hyperopia • Infrared (IR) Radiation (760-3000nm) • Lense Color Guide • Lens Color & Tints |
• Lens Materials |
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ABOC Certification:What is certification? You can't buy it; you have to earn it. Certification is professional distinction — official and public recognition of your achievement that you have met a national set of standards as a qualified and competent optician or contact lens technician. Certification is official assurance to the public that you will handle their eye wear needs competently and carefully; certification is recognized by employers as a standard of competence. Add (or add power): If there is a value under the 'add' heading, then you have a bifocal (or Progressive) prescription. Anti-Reflective Coating: This coating can be applied to the outside or inside surface of any lens (clear or sun lens) to minimizing the amount of light reflected by your lenses thus reducing annoying reflections and distracting glare which may cause headaches or interfere with vision clarity. Regular lenses reflect a very small amount of light back into your eye, possibly skewing vision; anti-reflective coating helps to prevent this anomaly. It is best used on the back surface of a sun lens to minimize back glare. Anti-Scratch Coating: This is applied to the outside of the lens to minimize the likelihood of accidental scratching. This does not make the lens scratch proof, but helps tremendously in reducing fine hair line scratches. All polycarbonate lenses come with an anti-scratch coating. ANSI Standard Z87.1: The new standard is now called the ANSI Z87.1-2003 standard, and is performance driven with two levels of performance for non-plano (prescription) lenses. ANZI Side shields Astigmatism: Astigmatism is one of a group of eye conditions known as refractive errors. Refractive errors cause a disturbance in the way that light rays are focused within the eye. Astigmatism often occurs with nearsightedness and farsightedness, conditions also resulting from refractive errors. Astigmatism is not a disease nor does it mean that you have "bad eyes." It simply means that you have a variation or disturbance in the shape of your cornea. What causes astigmatism? If the corneal surface has a high degree of variation in its curvature, light refraction may be impaired to the degree that corrective lenses are needed to help focus light rays better. At any time, only a small proportion of the rays are focused and the remainder are not, so that the image formed is always blurred. Usually, astigmatism causes blurred vision at all distances. Some people with very high degrees of astigmatism may have cornea problems such as keratoconus. Astigmatism is very common. Some experts believe that almost everyone has a degree of astigmatism, often from birth, which may remain the same throughout life. The exact reason for differences in corneal shape remains unknown, but the tendency to develop astigmatism is inherited. For that reason, some people are more prone to develop astigmatism than others. Axis: As mentioned above, a special cylindrical lens is needed in order to correct astigmatism. Not only does the strength of the cylindrical lens need to be specified, but the lens itself must be rotated into a specific position in order to provide the proper vision correction. The axis represents the amount of rotation of the cylindrical lens in degrees ranging from 1 to 180. Ballistic: Ballistic is any projectile in a high velocity. Our ballistic series far exceed ANSI Z87.1 safety standards as well military fragmentation standard MIL-STD-662. Base: The base is to the prism what the axis is to the cylinder. As you know, a prism is shaped like a triangle. The thicker the triangle at its base, the stronger the power. Much like the axis specifies the direction of rotation of the cylindrical lens for astigmatism, the prism must also be rotated into a specific position. But the rotation of the prism is simply specified as 'base in' or 'base out' (where 'in' means towards the nose) or 'base up' or 'base down'. Only these four positions exist as opposed to the 180 positions that can be specified for a cylindrical lens. However, orientations between these four positions can be specified by using combinations of horizontal and vertical prisms in the same lens. Base Curve: The base curve is the front curve of any lens. The higher the base curve (9 base) the more curved the lenses is thus making the frame more curved. Bridge Size: Is the distance between the lenses on any frame. Smaller bridge fits smaller noses. Contrast: Contrast is the difference in brightness between the light and dark areas of a picture, such as a photograph or video image. A high contrast lens gives you great visual acuity between light and dark areas in your view. CR-39 (plastic): The advantages of plastic is that it is lightweight and easily tinted to just about any color. One of the disadvantages is that those lenses scratch easily. Cylinder: If there is no value under the cylinder heading, then you have a very simple prescription. If there is a value under this heading, then you have astigmatism. The majority of optometrists write the cylinder value with a minus sign in front while the majority of ophthalmologists (physicians who specialize in the eye) write the cylinder value with a plus sign in front. Regardless of which way this is written, your glasses will be made the exact same way -- these are just two different ways to write the same spectacle prescription. Like sphere power, the cylinder power is also measured in diopters. Day and Night (photochromatic lenses): New photochromatic lenses are so smart they go from clear indoors to as dark as sunglasses outdoors. Their advanced technology adjusts to changing light, so you see clearly and more comfortably in virtually any light condition. Indoors, photochromatic lenses are as clear as your regular eyeglasses. Outdoors, they quickly darken, getting as dark as sunglasses if necessary. They work so well, in a recent clinical study, four out of five eyeglass wearers preferred photochromatic to their regular lenses, and photochromatic provide 100% UV protection. Ask your eyecare professional about making photochromatic lenses your every day lenses. And find out just how smart a lens can be. Diopter : A unit of measurement of the optical power of lenses. For example; if a person has a prescription of -4.00, that person has 4 diopters of power in their lens. Diopters generally are measured in quarter steps like -4.00, -4.25, -4.50. Some doctors refine their measurements down to twelfth steps like -4.00, -4.12, -4.62. Diopters are also used to measure prism. Eye size: Is the horizontal measurement of the lens on any frame. Larger eye size fits bigger heads. Flat Light: When light is "flat," the slope looks like a white, empty canvas, and it's impossible to read the snow surface clearly. Ruts, bumps, ice, even rocks and thin patches disappear. And if you're out in an open expanse, it's hard to determine the pitch of the slope as your depth perception shrinks to nil. Frame Measurements: What do the numbers located on the bridge and temples of the frames mean? Example: The numbers on the frame reflect the SIZE MEASUREMENTS in millimeters (mm). 1st Number (ex.54) = the width of the lenses
Glass lenses : One major advantage is that it is very scratch resistant. However it is double the weight of conventional plastic. Also it is not as shatter resistant or safe as plastic. Can easily be tinted. Grilamid Nylon Frames: No other material has the flexibility, remarkable toughness, and exceptional resistance to sun lotions. These elements allow our design team to combine the frame material's light weight, impact resistance, flexibility in variable temperature and overall comfort to create models that are durable and surpass all expectations. High index 1.56: Thinner and lighter than regular plastic good for higher prescriptions. Can easily tinted into sunglasses. High index 1.60: Thinner and lighter than 1.56 high index. These lenses already come with a scratch coat. Great choice for higher prescriptions. High index 1.66: Thinner and lighter than 1.60. These lenses already come with scratch coating. Also a great choice for high prescriptions. Hyperopia: Also known as farsightedness, is usually inherited. Children are often hyperopic which may lessen as an adult. Hyperopia is a refractive error, which results from a disorder rather than from disease. A refractive error means that the shape of your eye does not bend light correctly, resulting in a blurred image. Infrared (IR) Radiation (760 - 3000nm): Infrared Rays are radiant energy, or heat waves, not considered harmful under normal conditions. These heat rays cannot be seen but can be felt. If you are exposed to intense sunlight for a lengthy period of time (a day at the beach, for example) without infrared protection, you may experience a burning or stinging sensation in your eyes and a sense of fatigue. Infrared rays can be especially discomforting if you wear contact lenses. If your sunglasses fail to stop infrared light, it can be absorbed by your contacts, causing them to “warm up”. Lens Colors and Tints :The color of the lens is usually a personal decision, but here are some facts to keep in mind: Gray or green-tinted: Offer the least amount of color distortion; good for all-purpose use and clear days. Tip: Darker doesn't necessarily mean better. The darker the lenses, the more visible light they block. Brighter conditions demand darker lenses. It's important to keep in mind where you'll be wearing them most. Sunglasses designed for mountain climbing, for example, generally have lenses too dark for everyday wear.
Lens Materials:There are three major types of sunglass lenses: glass, polycarbonate and plastic. Glass lenses are the most scratch-resistant and distortion-free, but they are also heavier, more expensive and more likely to shatter. Macular Degeneration: is a degenerative disease that robs young and old of central vision. As a result, children face a lifetime of uncertainty and elders risk the early loss of an independent life. In addition to the support of long-term efforts in the fields of Stem Cell and Genetic research for an ultimate cure, we are particularly interested in promising near-term, scientific studies designed to inhibit the progression of macular degeneration and restore a measurable amount of vision to all. Nanometers: The measure of the length of a wave of light. One billionth (10-9) of a meter. Nose pad: One of a pair of pads, usually clear, that rest on either side of your nose and help to support your glasses. Melanin Polarized lenses : "The three main concerns eyecare professionals have with sunlight are UV radiation, Blue light, and Glare. This trio of challenges is often not addressed by most sun lenses, and those that do address them don't necessarily address them well. Polarized Melanin Lens gives ultimate protection against all three. Ultra-violet light is the high-energy, invisible light ranging from approximately 190nm to 380nm. The UVA portion (315nm to 380nm) is considered harmful to the eye-causing problems such as sunshine or brown cataracts, increased pterygium, and photokeratitis. Sources of UV include direct exposure from the sun and computer monitor as well as reflective surfaces such as water, sand, and snow. Blue light, or more accurately the blue and violet portion of the visible light spectrum, is the high-energy visible light (HEV), which research is beginning to indicate is a contributing factor to age-related macular degeneration (AMD). Visible glare is caused by sunlight reflected off surfaces such as water, roads, car windshields, snow, and sand. Polarized Melanin Lenses will be well suited to your active outdoor patients who are looking for a comfortable sun lens that is impact-protective and absorbs harmful light radiations. Consider it for boaters, hunters, skiers, hikers, forest rangers, police officers, or anyone who spends a good deal of time out-doors." * Mirrored Coating: Also called Flash Coating, it is applied to the outside of the lens and can be applied over any base color. New laboratory processes have created coatings that adhere better to the surface of the lens, are less susceptible to scratching, and are available in an expanded palate of colors. Mirror coated lenses absorb anywhere from 10 percent to 60 percent more light than uncoated lenses, depending on the type and degree of coating. The light transmission is further reduced by the base tint of the lens. Due to its reflective property, any mirrored lens will appear darker since it will reflect a certain amount of light trying to reach the eye. A mirrored lens will also add an extra buffer against glare. This makes them ideal for outdoor uses such as skiing. Care and Cleaning: Because most mirror coatings are applied to the surface of the lens, extra care must be taken when cleaning a mirrored lens to prevent scratching and other damage to the surface. Lens cleaning cloths should be used rather than abrasive cotton or paper towels. Dawn dishwashing soap is a good cleaner, but don’t use other household cleaners such as Windex. Super Mirrored Coating: Mirror coatings on eyeglass lenses serve the dual purposes of fashion and function. The fashion aspect is easy to understand. Simply look at entertainment and sports celebrities that wear the “cool” look of mirrored lenses. Function is a bit more complicated because of the wide variety of mirror colors and densities. The best selling colors of silver, gold and blue have different properties and manage different needs, and other colors serve niche needs. These fashionable and functional coatings however, have had limited appeal because of four major drawbacks:
The deep, rich hues of the new MAXXIMUS MIRROR solve the traditional problems of mirrored lenses. Myopia: Also known as nearsightedness, is inherited and is often discovered in childhood. Myopia is a refractive error, which results from a disorder rather than from disease. A refractive error means that the shape of your eye does not bend light correctly, resulting in a blurred image. Myopia often progresses throughout the teenage years, when the body is growing rapidly. People with high myopia have a higher risk of detached retina,which can be repaired with surgery, and glaucoma. Ocular: Ocular is anything of or relating to the eye. O. D.: O. D. simply means 'right eye'. It is the short form of the latin term 'oculus dextrous'. Photochromic: Able to change lens color or darkness/density depending upon the degree of exposure to light. Polarized Lenses: Light waves traveling freely can vibrate in any direction. When light strikes a horizontal reflecting surface such as water, sand or pavement, it vibrates horizontally creating glare. To the unprotected eye, glare can decrease depth perception., reduce visual acuity and create eye fatigue. Polycarbonate: Polycarbonate lenses or "Poly" are "impact resistant" thinner and lighter in weight than traditional plastic eyeglass lenses, they also offer ultraviolet (UV) protection and scratch resistance. In addition, they are very impact resistant. This extra toughness makes them the lenses of choice for children's glasses, sports eyewear and safety glasses. Presbyopia: Inability of the eye lens to focus incoming light, resulting in blurred vision at a reading distance and eyestrain. Most people develop presbyopia in their 40s. Prism: This is a box on the prescription form that is rarely filled in. Occasionally, when the two eyes are not properly aligned and looking directly at the same thing, prism can be ground into the lenses in order to re-align them. This can occur with strabismus (i.e. - an eye turn) or in situations where the eyes are properly aligned but are under a tremendous amount of strain in order to keep them aligned. The value under the 'prism' heading denotes the strength of the prism. Progressive lenses: (also, progressive addition lenses or PALs) Multifocal lenses whose corrective powers change progressively throughout the lens. A wearer looks through one portion of the lens for distance vision, another for intermediate vision, and a third portion for reading or close work. Each area is blended invisibly into the next, without the lines that traditional bifocals or trifocals have. Pupilary Distance (PD): The distance between the center of your pupils is known as the pupilary distance, this is measured . Before your prescription lenses are cut into the shape of your frame, the pupilary distance needs to be measured. This measurement is then used so that the optical center of each lens can be lined up with your pupils in order to give optimal visual clarity. In general, PD measurements fall in the range of 48mm to 73mm. The most common measurements are between 58mm and 68mm. Selective Light Filtration: The act of filtering a certain wave of light. An amber or yellow lens often filters the blue wave of light giving a sharper high contrast view of the world. Impact Resistant: Resistant to shattering or splintering. impact resistant plastic is made so that it will not break into small pieces. Polycarbonate is impact resistant making it a very safe lens to wear. Sphere: The number under the heading 'sphere' is the main part of your prescription. The number itself denotes the strength of the lens as measured in diopters. A diopter is a unit of measurement that is simply the inverse of the focal distance of the lens as measured in meters. For example, if a lens has a strength of 2 diopters, then parallel light rays that pass through this lens will focus together at a distance of 1/2 meter (50 cm) away from the lens. If you are near-sighted (i.e. - you have trouble seeing far away but can see fine up close), then you can make a rough calculation of the strength of your glasses. Temple Length: Is the length of the "arm" of a pair of glasses, running from the ear to the lens area in Millimeters. Photochromatic Lenses (Day and Night): New photochromatic lenses are so smart they go from clear indoors to as dark as a light sunglasses outdoors. Their advanced technology adjusts to changing light, so you see clearly and more comfortably in virtually any light condition. Indoors, photochromatic lenses are as clear as your regular eyeglasses. Outdoors, they quickly darken, getting as dark as sunglasses a Sunglasses "2" if UV is present. They work so well, in a recent clinical study, four out of five eyeglass wearers preferred photochromatic to their regular lenses, and photochromatic provide 100% UV protection. Ask your eyecare professional about making photochromatic lenses your every day lenses. And find out just how smart a lens can be. Ultraviolet (UV) Radiation: Solar radiation is formed by visible and invisible light waves. Measured in nanometers, it has three wave lengths that reach and affect your eyes: Ultraviolet, Visible Lights, and Infrared Radiation. The shorter the wavelength, the more damage to your eyes. Ultraviolet Radiation (200 - 380 nm) UVC (200 - 290 nm) UVB (290 - 320 nm) UVA (320 - 380 nm) Protection from harmful UV radiation is becoming more and more important as the earth’s ozone layer continues to be depleted. Contrary to what you might think, clouds do not block out all UV rays. Though thick, heavy clouds absorb most UV radiation, UV will pass through thin clouds, even when the sun’s rays don’t feel hot. And watch out for haze – it doesn't’t block UV radiation at all. You get higher exposure to UV radiation on snow, sand, water, or concrete, since these surfaces reflect the sun’s rays. You will also get higher UV radiation levels at higher altitudes and at areas closer to the equator. To make matters worse, the damaging effects of long-term UV radiation exposure are cumulative with the consequences not immediately apparent. So beware: excessive exposure to UV radiation today can cause eye problems tomorrow. Therefore, a good pair of sunglasses is essential for enjoying the sun. The filtering qualities of the lenses must be considered so that you have the correct type of lens for your intended use. There is no point in buying lenses designed for high altitude if you use them for everyday urban life. UV Filter (coating): This coating is a filter for the harmful UV radiation. The coating is either put on the lens or is imbedded into the lens to protect your eyes for the harmful effect of the sun’s UV radiation. Visible Light (380 - 760nm): Visible light is that portion of the light spectrum that the eye perceives as color. In this spectrum, protective eyewear deals with glare or the brightness of the sun. Excessive amounts of visible light are irritating to unprotected eyes and can reduce your visual perception by as much as 50%. It can also hinder your eye’s ability to adjust to darkness (night blindness) and cause difficulty in depth perception. The unprotected eye strains to focus (squint), which can cause wrinkles and chromatic aberration. Athletic Optics offers a variety of lens colors to enhance your vision in various lighting conditions. Blue Light (380 - 480nm): Closest to the high energy, UV portion of the visible light spectrum, it focuses in front of the retina rather than on it, which blurs vision, reduces contrast and hinders depth perception. Windless Eyewear :will enclose and seal your eyes from the elements. Venting of the lenses allows slight airflow to keep the lenses from fogging and keeping your eyes from excessive wind irritation (great if you wear contacts). These glasses come with 100% UV protection along with diverting wind, dirt or snow. Checkout our Windless Eyewear. Sunglasses by PanOptx Wrap or Wrap around: Wrap glasses are those that curve around the curve of a person's face fitting close to the head. *Source - Drake, Diane. "SunRX Polarized Melanin Lenses Provide Ultimate Protection." Vision Care Product News. June 2004 |
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