When you have successfully chosen a stylish frame and now it’s time to
choose your lenses, it can be a challenge to understand the different
lens types, materials, and options. That is why we have experienced
doctors and opticians to help you customize your prescription lenses.
First we need to decide on Lens Type:
Single Vision
Single vision lenses have only one distance and that prescription encompasses the entire lens. Most patients are put in single vision lenses when they start wearing glasses as we age and depending on our lifestyle we might need different single vision lenses for different tasks such as driving, computer, reading, sewing, piano distances, etc.
Bifocals
When we hit that magic age of forty or sometimes younger, the muscles that holds our lenses slowly loses their ability to flex the lens, therefore resulting in decreased accommodation or focus. After this happens it makes it harder to see and focus in at different distances especially to see at near. At this stage most patients would chose to put in a bifocal lens. There are many different bifocal lenses. The most common is a flat top 28mm lens. Flat top 28 lenses are a half moon shaped addition to the lenses where the line is usually measured at your lower lid. That line indicates where the top distance stops and the reading distance begins. There are also flat top 35 mm lenses which indicate that the bifocal part is larger with 35mm in length. Executive bifocals have a line going through the whole bottom part of the lenses for full reading at the bottom half of the lens. Double segment bifocal lenses are usually for occupations such as plumbers, mechanics, computer repair jobs etc. that requires you to view up to read. Blended bifocals came before the invention of progressives and are not as widely used as much. These lenses has the edges of the bifocals slightly blended into the lens to hide the line appearance of the traditional bifocals.
Trifocals
Trifocal lenses are commonly used if your lifestyle and prescription requires a distance vision, a computer vision and a reading distance in your glasses. A trifocal lens unlike bifocal lenses has two lines running across the half moon shaped of the lenses. The top of the lenses are designed for distance viewing the first half of addition is computer and the bottom half is for reading. Most patients are usually put in trifocals when they do not adapt to progressive lenses and is active at both computer and reading distances.
Computer/Office Lenses
Computer lenses are lenses that are set are you computer distance. They can be single vision lenses that are set at your computer or working distance or can be a combination of bifocal for computer and reading or blended so that you do not see the line.
Progressives
Progressive lenses offer the benefit of reading fine print while eliminating the visible line of a traditional bifocal or trifocal lens. A progressive lens is a multifocal lens, which offers clear vision from distance to near. Progressive lenses may be designed for specific uses, for instance, a computer progressive lens may offer a large focused area for computer and reading. A lens such as this may be useful for those that spend much of their day looking at computers and documents. First time progressive wearers often require an adaptation period before becoming fully comfortable wearing the lenses. Due to the inherent design of progressive lenses, minor aberrations occur in the peripheral areas of the lenses. As technology improves, peripheral aberrations have been continuously reduced. Most first time wearers are comfortable with progressive lenses almost immediately and is now the standard of choice for most patients.
Digital or High Definition
(Digitally Surfaced or Cast Molding Processed Lenses)
Do you have 20/20 through your current pair of glasses, but still feel as if your vision can be sharper? Digital lenses may be the solution to your problem. Digital lenses correct for higher order aberrations that conventional lenses do not correct. A higher order aberration causes image distortion, especially in conditions such as night time driving. The fabrication of digital lenses takes into account the position of the lens in relation to the wearer’s eyes to optimize the lens power. Digital lenses are recommended for all patients; however individuals with higher eyeglass prescriptions may notice a greater benefit than those with mild prescriptions.
Second we need to decide Lens Materials:
Plastic or CR39
Outstanding optical quality and low cost. Lower index material, thicker and heavier than other materials and not shatter resistant. Recommended Rx range -2D to +2D.
Polycarbonate
Shatter resistant and impact resistant. Is suitable for sports with children and teens, and certain occupation such as firefighters, police officers, and patients with a weak or lazy eye. Thinner and lighter weight than plastic. Lower optical quality than CR-39, recommend anti glare coating to increase clarity. Recommended range -3D to +3D.
Trivex
Shatter resistant, suitable for sports and children/lenses. Thinner and lighter weight than plastic. Superior optical quality to polycarbonate, similar to that of CR-39 lenses. Recommended Rx rage -4D to +4D.
Acuity 155
The latest lens material that has a lens index of 1.55 and is lightweight, has UV protection, but is not as impact resistant as polycarbonate.
Hi Index
Lastly we need to decide on Lens Options:
Aspheric Lenses
Improves cosmetic appearance of glasses by allowing the prescription to be thinner and flatter than conventional non-aspheric lenses.
Anti Glare Coating
Makes the eyes more visible, as if lenses are not being worn or more transparent. Reduces reflections from lamps, overhead lights, and computer screen glare as well as car headlights when worn at night. Crizal Alize anti glare coating adds scratch resistance and a hydrophobic coating to repel dirt and smudges.
Transitions
Transitions reduce the need for two separate pairs of glasses. These lenses are clear indoors and darken automatically in the presence of ultraviolet radiation. Transitions are important for children, who tend to spend more time outdoors than adults, resulting in increased UV exposure. It is important for parents to protect the eyes of their children, similar to applying sunblock to skin before outdoor activities. The drawback to transitions is that they are not suitable under daylight driving conditions. These lenses are offered in gray and brown tints.
Polarization
Polarized lenses reduces glare in sunglasses.
Scratch Coating
Scratch coatings are added to lenses to help protect to surface of lenses from minor scratches. Since polycarbonate and trivex lenses are scratch resistant a coating does not need to be added to theses lenses.
Tints
Many different colored tints are available to added to your lenses such as brown, grey, blue, rose, etc that can help you achieve that cosmetic look or help with certain conditions such as fluorescent lighting sensitivity and possibly dyslexia.
UV Coating
Most plastic lenses do not come with UV coating so can be added to protect your eyes from the UV before we make them into sunglasses.
Edge Polish & Edge Tints
Edge polish can be added to lenses to make the edges of your lenses have a nice shine to them. Edge tints can be added to lenses to make them have interesting colors at the edge.