Eyecare Lens Guide
2
2
Produced for T Mobile in association with Eyecare International
Quick reference lens guide Types Single Vision Bifocal Varifocal
page 5
page 6
page 7
Materials CR39 High Index Polycarbonate Glass Glass
page 9
page 10
page 11
page 12
page 13
3
How to choose the right lenses for you The stronger your prescription, the thicker and heavier your lenses will be. Lenses prescribed to correct short sight are thicker at the edges, and thorse for long sight are thicker at the centre. Every lens material can be thinned down or enhanced with treatments and coatings to suit your image and lifestyle. As with eyewear frames, the material used to make your lenses determines whether they are light, heavy, thick, thin, tough or brittle.
Lens Types Whatever your prescription, it will be most compatible with one of three types of lenses: single vision, bifocal or varifocal. While single vision lenses are designed to correct a single weakness, varifocal and bifocals tackle distance, intermediate and close reading issues.
4
Single Vision Simplest form of lens for glasses. Made to a single prescription, to correct a vision weakness at one type of distance. Qualities The curvature, thickness and weight of a single vision lens, depends on the amount of long or short sight it is designed to correct. Use For common complaints from long and short sight, to reading difficulties. Wearer Suitable for most people and often prescribed to assist with reading. Frames This highly affordable and widespread lens type is one of the most popular and can be found in prescription glasses, to ‘ready readers’ bought over the counter
Short sight correction
With
Without
With
Without
Long sight correction
5
Bifocal Bifocal lenses are split in two, with the top half correcting near vision and the bottom half for distance. Unlike varifocals however, these lenses contain a distinct dividing line between the two different prescriptions. Qualities Bifocals come in a range of designs. Each type combines a prescription for near vision and long distance problems within the lens, in different ways. Wearer Commonly used to assist people that have general visual deterioration, but need a different prescription for close work or reading. When doing screen work, the top part of an occupational bifocal corrects intermediate vision while the bottom portion aids near vision reading. Frames For strong bifocal prescriptions a full frame, rather than a supra or rimless frame is recommended. This guarantees that your lenses can be the thinnest and lightest avaliable. Choose rimless frames and the lenses will have to be thick enough to support bolts either side to adjoin the frame arms.
Distance vision correction
6
Near vision correction
Distance and near vision correction
Varifocal Designed to correct distance, intermediate and near vision. Varifocal lenses blend gradually from a distance prescription at the top, through to a reading prescription at the bottom. Qualities Varifocals are the new bifocals! Although both contain multiple prescriptions in one lens, there are no visible dividing lines between the near, intermediate and distance corrections in varifocals. This instantly enhances their cosmetic appeal. Use These complex lenses correct long and short sight, and help with reading. Wearer Usually prescribed to the 40+ age group to help with reading and computer work. The occupational varifocal aids wearers who have a problem with getting sharp focus on the screen in front of them, but don’t need a distance prescription. Frames The reading area of varifocals gets cut away if you go for shallow frames so it is practical to look for full rim styles. Also be aware that as varifocals contain different prescriptions in every part of the lens, it’s imperative that frames sit at the right height on your face.
Near vision correction
Intermediate vision correction
Distance vision correction
Near, intermediate and distance vision correction 7
Lens materials The material you choose for lenses will inuence their thickness and weight, along with the size and shape of your frames. Your decision will be determined by a host of factors, including personal prescription, frame selection, lifestyle and level of activity.
8
CR39 CR39 is the standard lens material for glasses. At approximately 50% lighter than glass, this is a plastic lens that offers better ultraviolet (UV) light protection, less likelihood of shattering and can be tinted more easily. Qualities A basic plastic lens that is affordable and readily available. Use The practical choice for those with minor visual deďŹ ciencies and a simple prescription. Wearer Suitable for anyone and great if you’re looking for an inexpensive lens that doesn’t require additional thinning and coatings. Frames Typically suited to full rim, plastic frames, or basic metal frames made from conventional materials like stainless steel.
9
High Index The thinner the material, the better it looks in your frame. This makes high index lenses the best choice, even for those with strong prescriptions. It is thinner and lighter than standard CR39 and is available in four different varieties ranging from thin to super thin. Qualities Thinnest, lightest resin lens available. This material can bend more light, through less thickness,making lenses compatible with all prescriptions and frames. Use Recommended for a thinner version of any lens type and prescription as it provides a better cosmetic appearance. Wearer Great for those with a strong prescription who want to make their lenses thinner and lighter. Frames Suits the widest range of frames available. Ideal for half rim or rimless glasses as it is thin, lightweight and suits a discreet frame.
10
Polycarbonate Polycarbonate lenses are more impact resistant than standard plastic lenses and less likely to break under force. They are also much thinner, lighter in weight and have built-in ultraviolet protection. Qualities Strongest lens material available. Use First choice for specialist safety glasses, sports goggles and children’s eyewear. Wearer For anyone that works in an industrial environment polycarbonate is more shockproof than any other material. It is also the most durable for sports and active wear. Parents in particular should choose polycarbonate lenses for kids, to protect them from accidental eye injury. Frames Used in safety glasses, sports goggles and rimless frames where lenses are more exposed and at risk of being chipped or weakened.
11
Glass The traditional lens material. Glass provides the clearest optics of all lens materials, but is twice as heavy as any plastic and offers less UV protection and impact resistance. Qualities Thinnest, heaviest and most scratch resistant material available. Use Rarely used now, except for people with greatly impaired vision and exceptionally strong prescriptions. Wearer Glass lenses are still the thinnest available. They are usually the primary choice of older people who are used to the material and have been wearing it for years. Frames As this material is quite heavy it can cause frames to slide down the nose frequently. This makes it more important to team glass lenses with sturdier, full rim frames that maximise comfort. Rarer Glass sightings Light bulbs, thermometers, test tubes
12
Lens Coatings Coatings can enhance the performance and appearance of lenses, making your glasses more functional and fashionable. Choose from options like anti-reflective, scratch resistant and water repellent to tailor lenses exactly to suit your lifestyle. Scratch Resistant No lens material, not even glass, is totally scratchproof. However, a lens that is treated front and back with a clear, hard coating does become more resistant to surface scratching. Multi Anti Reflection MAR coatings build up several layers of UV protection on your lens. This helps you see through the lens better and prevents reflective glare from obscuring your eyes. Oleophobic This anti-smudge outside layer of an MAR coating is applied to repel grease and oil, making lenses easier to clean. The higher the quality of this layer, the less oil is deposited on the lens when it is touched. Hydrophobic When liquids hit your lens this coating acts like ‘invisible windscreen wipers’ by causing them to roll right off again. This prevents common deposits like perspiration and water from impairing visibility. Super Hydrophobic To prevent lenses from steaming up in intensely wet conditions, super hydrophobic coating includes an anti-fog additive. Polarised Polarised lenses are treated with a 100% UV proof tint that is commonly grey or brown. They are typically used to make sunglasses. Transition The UV filtering properties of transitions causes these lenses to automatically darken when you step outside and return to normal when you go back indoors. Tint Tinted lenses offer protection and comfort by shielding your eyes from direct sunlight and reducing light energy and glare.
13
Quick guide to lens materials Lens material
Qualities
Use
Wearer
Frames
CR39
50% lighter than glass UV protection Easy tint Affordable
Basic prescriptions Minor visual deficiencies
Everyone
Full rim, plastic Conventional metal
High Index
Thinnest plastic Four varieties – thin to ‘super thin’
Any lens type and prescription
Everyone Strong prescriptions
Ideal for half rim or rimless
Polycarbonate
Industrial Strongest strength available Thinner, lighter lenses Built in UV
Everyone Sporty, Active Parent, Children
Rimless Safety glasses Sports goggles Children’s eyewear
Glass
Thinnest of all Heaviest Most scratch resistant
Anyone already accustomed to its weight and feel
Full rim Sturdy
Strong prescriptions
Lens care checklist 1. Never place glasses facedown. 2. Don’t use clothing or tissues to clean your lenses 3. Choose scratch resistant lenses to avoid permanent marks that will impair your vision. 4. Use both hands to put on and remove your glasses to preserve the frame shape. 5. Avoid letting others put on your glasses as this can disturb the frame alignment.
14
15
Eyecare