All of Eyemart Express' lenses are made with CR39 plastic. Plastic lenses in CR39 monomer lend fewer chromatic aberrations (halos, double vision, glare, etc.) compared to polycarbonate lenses, as measured by the Abbe number (measurement of the material's light dispersion). This plastic lens is lightweight compared to glass, and may be crafted in just about any prescription, though many people with higher prescriptions prefer it. The higher the index, the thinner the lenses. Plastic lenses are great for prescription sunglasses due to their tintability factor. You can virtually tint a plastic lens in any color of the rainbow.
During the checkout process, you can upgrade to polycarbonate lenses. Introduced to the ophthalmic lens market in the late 1970s, polycarbonate lenses are the safest ones available as well as being thinner and lighter than standard plastic lenses. Polycarbonate possess an ultraviolet (UV) filter and are particularly popular in children's and safety eyewear due to their impact-resistant quality.
Trivex has slowly increased in popularity and availability and is the only lens material other than polycarbonate to pass the FDA's Impact Resistance Tests. While Trivex has a slightly lower refractive index (1.53 compared to 1.58), its specific gravity makes it the lightest lens material currently available. Like polycarbonate, Trivex also has inherent UV protection and is highly resistant to cracking.
High Index Plastic
High-index lenses are plastic's alternative to polycarbonate and are used for stronger prescriptions. Due to the refractive qualities of high-index, these lenses are the thinnest available. This allows those with stronger prescriptions to have more frame options and 'thinned out' lenses. For most prescriptions, high-index lenses offer the same optical clarity as plastic lenses in a significantly smaller package.
Anti-scratch is a scratch-resistant coating permanently bonded to a lens to help reduce hairline scratches common to most lenses, while also making the lens more durable. Though a lens treated with this coating is not 100-percent protected from scratches, it does prevent minor ones that would otherwise appear if a coating were not in place and reduces the noticeability of these scratches when they do occur. Anti-scratch coating is completely invisible and doesn't affect the clarity of a lens.
This premium coating is ideal for night driving or frequent computer use. It not only improves your vision, it also reduces light reflected off the lenses, so others can see more of you and less of your glasses. Allowing more light to pass through the lens also increases contrast and therefore increases visual acuity. Another benefit of anti-reflective coating is that wearers often find their eyes are less tired, particularly at the end of the day.
Tint is just that — a shade (a shade of gray or brown in our case) that simply lowers light level without filtering it. Some advantages of tinted lenses include decreased glare, lowered brightness and reduced fatigue and eyestrain. Tint also protects eyes from harmful UV rays that can lead to cataracts and other optical issues.
Polarized lenses block certain types of light waves. Sunglasses and camera lenses are often polarized to reduce glare from surfaces, such as light reflecting off a lake or the hood of a car. Somewhat like the way Venetian blinds control the amount of sunlight passing through a window, polarization blocks as much as 50% of the light passing through a lens. The person looking through the lens can still see clearly in most cases but it reduces the brightness and glare of light.
The Photochromic Sunglasses Package Option includes UV-protected lenses that change from clear to dark in the presence of sunlight then back to clear when you are indoors. Photochromic lenses make clip-on sunglasses or switching to prescription shades a thing of the past. Once you've selected frames and entered your prescription, you may then choose the Photochromic Sunglasses Package Option and your frames will include UV-protected lenses. Simple!
Choose this option if your lenses are for one fixed correction: nearsightedness (to see far away), farsightedness (to see close up) or intermediate (computer screen distance). So as long as there is no 'add power' listed on your prescription, select single vision.
No-line progressive bifocals, which allow you to seamlessly and fluidly move between the upper and lower prescriptions, are without the line found in traditional bifocals. People won't even know that you are wearing bifocals!
Standard lined bifocals offer far-distance correction in the main part of the lens, with a smaller area below for near-vision correction. This section may be half-moon-shaped, round, rectangular or it can take up the entire bottom half of the lens. These are the most common type of bifocals because they allow people with myopic or hyperopic conditions to use a single pair of glasses for both distance and near vision.
Similar to a lined bifocal except this type of prescription offers three areas of vision correction. The standard distance viewing and reading sections of a bifocal are present, but there is also an intermediate section for viewing a computer screen or other near objects.
Eyemart Express is proud to offer high definition lenses. Dr. Barnes' High Definition Lenses are digitally surfaced on both sides. The advanced manufacturing process reduces higher-order aberrations occurring in lenses created with traditional lens manufacturing tools and processes. The included anti-reflective coating also reduces glare, halos, blurring and starbursts. Also known as digitally surfaced lenses, high definition lenses enhance an image's clarity 10 times more accurately at all points of the lens. The focus is crisp and the clarity is brilliant. It's like looking at the world in high definition!