Prescription lenses help people see better by correcting the natural refractive errors of the eye, like nearsightedness, farsightedness and astigmatism. Lenses work by refracting, or bending light, so that it focuses at a single point on the retina, in the back of the eye. Light that is properly focused like this produces clear vision.
Finding the right material for your lenses matter. We want to understand what you want to do in your daily life and your recreational activities. Taking the time to understand you and your lifestyle allows us to recommend the right material for your lenses so that you can see better and have the best protection possible.
There are a variety of lens materials available today, unlike in the past, when glass was the only option. Which material is used for your lenses may depend on what you intend to used the glasses for, on the appearance of the lenses and on safety issues. Plastic lenses are most popular today for many prescriptions, but glass lenses are still used for some applications. High-index plastics are especially useful for strong prescription lenses, because they minimize lens thickness and weight. Some plastics, like polycarbonate and Trivex, are remarkably impact-resistant and are used to make lenses for safety glasses, for children, and for playing sports. Photochromic materials, which darken when exposed to ultraviolet (UV) light, are useful if switching from clear lenses to sunglasses is inconvenient. With photochromic lenses, one pair of eyeglasses can often suffice. Unfortunately, UV rays are blocked by car window glass, so tinted sunglasses may still be necessary in the car.
Lens technology continues to advance, and far better eyewear lenses are available today than just a few years ago. One of the innovations is the aspheric lens, which is curved differently from the center to the edge of the lens. This results in less optical distortion, a larger usable portion the lens, and a finished lens which is flatter and thinner than previous designs. As frame materials have improved, the options for mounting lenses have multiplied. Drill-mounted lenses, which don’t have a full frame, at all, are increasingly popular. When worn, the eyewear is nearly invisible.
Single vision lenses help provide clear vision at a particular distance. For most people, these glasses are ideal until they become 40 to 45 years old. Children and young adults In that interval, presbyopia develops, in which the eye’s natural lens stiffens. As the lens hardens, focusing up close becomes difficult, and activities like reading a book and threading a needle become harder. To deal with this age-related change, there are several excellent options. The simplest is to have two pairs of single vision glasses—one for reading and another for seeing in the distance. But using this strategy involves switching from one pair of glasses to another, perhaps throughout the day.
To avoid this glasses switching, bifocal lenses were developed. Bifocal lenses, like their name suggests, have two lens segments—the upper part for viewing in the distance and a lower segment for viewing things up close.
Trifocal lenses: take this strategy a step further, adding an additional segment in between the distance and near zones to view objects at arm’s length. By adding an additional intermediate zone, however, the segment height is reduced.
Progressive addition lenses: are another popular option. By smoothing the transition zones, they eliminate the lines between the segments. Wearing this kind of lens gives the full range of vision, activated by lifting and lowering the chin to view objects from different zones in this multifocal lens. From a cosmetic standpoint, the progressive lens has a distinct advantage—since there are no transition lines in the lens, it looks similar to a single vision lens and gives no clue about the age of the wearer.