Progressive lenses are often prescribed for people suffering from presbyopia, which usually affects people over Presbyopia usually occurs at around age 40 , when people experience blurred near vision when reading, sewing or working at the computer. Even people who are nearsighted will notice that their near vision blurs when they wear their usual eyeglasses or contact lenses to correct distance vision.
This is why progressive lenses are ideal for patients who have presbyopia — a vision condition marked by a decrease in the ability to focus sharply on nearby objects. As we age naturally, our ability to see nearby objects and objects in the distance can decrease.
Progressive lenses address separate visual needs in one lens. And it is also why progressive lenses are ideal for patients who have presbyopia.
However, as this study reveals , progressive lenses are also used to reduce the progression of myopia. Progressive lenses can correct astigmatism but are not solely used for astigmatism correction. Astigmatism is when the eye is no longer spherical, but more football shaped.
That sends light to different parts of the eye instead of at the center. Patients with higher prescriptions can still benefit from progressive lenses. The industry standard has mostly moved away from using glass lenses because they are significantly heavier than more modern materials and can make wearing glasses uncomfortable.
CR Plastic works well for low prescriptions and has an optical clarity comparable to glass. Polycarbonate has become the industry standard for lenses.
Hi-index lenses have a higher optical clarity than polycarbonate and are high-tensile, which is great for drill-mounted or rimless frames. The difference in thickness between 1. Locations Clancy Optical West. Spex Contemporary Eyewear.
Contact Us. Regardless of the type of free-form lens, the placement of the actual progressive optics, whether on the front surface, back surface or split between both, has minimal impact on the magnitude of the inherent unwanted astigmatism of the design. Consequently, the inherent unwanted astigmatism of progressive lenses is not significantly influenced by placement of the progressive optics Figure 2.
Although the inherent astigmatism may not differ appreciably, placing the progressive optics on the back surface can minimize unwanted magnification effects. Placing the progressive optics on the back surface of the lens eliminates the contribution of the front surface to these magnification changes.
Moreover, because the progressive viewing zones are brought closer to the eye, slightly wider fields-of-view may be obtained when the progressive optics are located on the back surface. Nevertheless, the differences in optical performance due only to the placement of the progressive optics are generally small. When free-form surfacing is utilized in conjunction with sophisticated optical design software capable of designing progressive lenses on the fly, however, it becomes possible to match the optics of each progressive lens exactly to the visual requirements of the individual wearer, prior to fabrication.
Given the inherent limitations of traditional progressive lenses, this application of free-form technology offers the most meaningful visual benefit. Semi-finished progressive lens blanks are factory-molded in mass quantity.
Just like you can take an off-the-rack pair of pants and have it customized to fit your specific measurements, you can now have lenses made customized for your specific prescription and frames. Free-form technology is the next revolution in vision correction. In addition to the improved visual clarity that customized free-form lenses provide, you can expect:. While everyone can benefit to a certain extent from customized lenses, people with complex prescriptions and progressive wearers will notice the greatest visual improvements.
The resulting prescription provides the best balance of vision, including improved night vision. This way, the lenses are made for variations in the eyes through the surface of both eye lenses.
This can benefit the efficacy of the dominant viewing regions deprived of unreasonably optical performance. This way, the user can completely enjoy adequate reading value through the major observing zones imaginable, irrespective of any frame size. At Goggles4u, one of the top-ranking online prescription eyeglasses stores, is now offering Free-form progressive lenses and other well-known and demanding lenses at best prices guaranteed.
Free-form features aspheric and atoric designs resulting in thinner, lighter lenses and more defined vision than standard lenses. If you wear contacts more than your glasses, but are looking to change it up a little, this lens is also perfect for you! This information is ultimately used to drive the production generator and polisher used to manufacture the lens. Some lens designs place both the progressive design and the power parameters on the backside. Others use both the front and back surface for powers and progressive designs.
Some require a distance measurement as well to approximate the distance from the back surface of the lens to the front surface of the cornea, but most do not. Whatever the requirements, the resultant lens can be significantly more accurate than any lens currently available on the market and provide the user with a new level of clarity.
This is typically done by using two tools—a roughing tool to crib the lens and to generate the surface curves to a reasonable quality, then a single-point diamond tool to skim the surface of the lens, leaving a finish that can be polished using a CNC polisher and a soft, rotating tool also driven by three-axis or more technology and the operating software.
Power tolerances of less than 0. Most lens manufacturers are already providing their patented designs of lenses produced using free-form technology…with millions of satisfied patients worldwide already wearing them. Jim Grootegoed is professional editor of Optical Lab Products. TheraBlue Lenses. CrownView Lenses. Shamir Autograph InTouch Lenses. See promotional flyer s for details:. Current Optical Promotions. All Rights Reserved. Contact Lenses.