Glossary of Terms
Anti-Reflective (AR) Coating: Also know as anti-glare, anti-reflective coatings improve the quality and the value of your lenses. An anti-reflective coating reduces disturbing reflections. It makes your lenses more attractive. And you will experience the most precise, crisp and clear natural vision in a brilliance that is not possible with uncoated lenses.
Bifocal: Corrective eyewear lenses containing regions with two distinct optical powers, such as distance and reading. A lined bifocal has a distinct line separating the two powers. A progressive lens has no visible line showing.
Crizal Easy Premium Anti-Reflective Coating: Crizal Easy offers premium glare and scratch protection, along with smudge resistance. Crizal Easy also adds UV protection equivalent to SPF 25.
Edge Polish: If you are ordering rimless eyeglass lenses, you may opt to have the cut endges of your lenses polished to a transparent shine.
Eye Size: The first number used in eyeglass frame sizing. This number indicates the width of the lens opening and does not include the frame material. It is measured in millimeters.
Frame Size: Eyeglass frames are measured in millimeters. The size is written like this: 52-18-145.
- The first number (52) is the distance across one of the eyeglass lenses, not including frame material.
- The middle number (18) is the distance across the nose bridge on the eyeglass frame. This is also refered to as the DBL, distance between lenses.
- The last number (145) is the length of the eyeglass temple, the part that goes back behind your ear. It is meaured from the end near the hinge to the very end following the curve.
Your frame size is generalized as one of the following to aid in your frame search:
- Small: frames measuring 44mm or smaller
- Medium: frames measuring 45mm-51mm
- Large: frames measuring 52mm-59mm
- XL: frames measuring 60mm and above
Glass Lenses: Glass is one of the hardest materials used to make eyeglass lenses. It also offers some of the best optical quality available. Glass lenses are physically heavier than plastic lenses and are not suitable for half-rimess or rimless frames. Glass lenses run the risk of shattering when dropped or misused.
Lens Packages: When ordering single-vision or progressive plastic, polycarbonate or high index lenses from Eyeglass.com, you may choose from one of the following lens packages:
- Value Package- This package includes standard plastic, 1.49 index lenses. These lenses have a factory scratch coating, but no anti-reflective coating. This lens package is suitable for full-rimmed frames only.
- Standard Package- This package includes polycarbonate, 1.59 index lenses. These lenses are multicoated with factory scratch coat and anti-reflective coatings. Polycarbonate is innately UV resistant, offering 100% UV protection. It is also shatter-resistant making it the perfect choice for children's glasses, safety glasses, sports goggles as well as half-rimless eyeglass frames.
- Premium Package- This package includes high index 1.60 lenses. A higher index allows for a natually thinner, lighter lens with the same precription correction as standard plastic. The lenses are multicoated with factory scratch coat and anti-reflective coatings and offer the same UV protection as polycarbonate lenses.
- Ultimate Package- This package includes high index 1.67 lenses. These are the thinnest, lightest lenses we offer. They are multicoated with factory scratch coat and anti-reflective coatings and offer the same UV protection as polycarbonate lenses. This package is suitable for those with high vision corrections.
Photochromic Lenses: These adaptive lenses automatically turn dark in bright light outdoors. Because they are activated by UV (sun) light, they may not darken completely behind the protection of your car's windshield. We use the Transition brand photochromic lenses.
Polarized Lenses: These are permanently dark sun lenses containing an additional filter to cancel out most of the horizontal light reflection. This significantly reduces your glare and allows you to see through harsh conditions.
Progressive Lenses: These are also known as no-line bifocals. Standard progressive lenses have 2 distinct optical power which are blended so no visable line exists. Premium progressive lenses offer higher tech blending to allow for an additonal middle focal point suitable for arm's length focus such as your computer screen.
Pupil Distance (PD) Measurement: This is the distance, measured in millimeters, between your pupils. It is crucial measurement when making prescription lenses as it tells the optician where to place the focal point of your new corrective lenses. You may obtain your PD measurement from anyone who has made glasses for you in the past. Your PD usually does not change once you become an adult.
Scratch Coat (Anti-Scratch Coating): This is a clear coating on all our eyeglass lenses that protects the lens surface from scratching. This coating is intended to protect from every-day threats such as dust and eyeglass cleaning cloths. Shold you need more protection, consider a harder lens material or premium coatings such as Crizal Easy.
Trivex: Trivex is a lens material made spicifically for rimless eyeglass lenses. It is harder than any other plastic so that your drill mounted frame fits the lenses perfectly from day 1 to day 701. You are upgraded to Trivex with the purchase of lenses with the rimless drill surcharge.
Varilux Comfort Premium Progressive Lenses: As the world’s most recommended progressive lenses, Varilux Comfort lenses offer smooth transitions from near, far and everything in between. That means less strain for your head and neck, making reading and everyday wear more comfortable than ever.