Single vision lenses are ideal for wearers’ who wish to correct only one distance. If these lens produce to correct for far distance, wearer should accommodate to see clearly up close. Single vision lenses also use by people who suffer with presbypia and hyperopia. In generally these lenses are considered as safe and have ability to provide better visual correction and avoid visual discomforts, eyestrains and headaches. Single vision lenses determined by an Optometrist and made by qualified by an optician.
In generally, upper part of the bifocal lens are used for distance vision and lower segment are used for near vision. The lens which caters to near vision referred to as ‘add segment’ and various types of shapes, positions and sizes are available for add segment. They are used to fulfill visual demands of the eyeglass wearer as well as to complete different functions of the lens. Bifocals are ideal for wearers’ who suffer from presbyopia. Bifocals allow clearly at distance and near without removing the eyeglasses.
Except two focal areas which are separated by third in the middle, Trifocal lenses are just like Bifocal lenses. There are two segment lines in trifocal lenses which are dividing into three different correcting segments. Trifocal lenses used to correct the vision of the wearer for intermediate distances roughly at arm’s length. Trifocal lenses are mainly used in adjusting computer distance.
Lenses which are used to provide smooth transition from near correction to distance correction, eliminating segment lines and providing much clearer vision at all distance identified as Progressive addition or varifocal lenses. Progressive lenses lack of any sort of abrupt change in power and present uniform appearance to the wearer. As a result of that progressives also named as ‘no-line bifocals’. Progressive lenses have ability to protect the eyes upon variety of tasks.
Polycarbonate lenses produce from plastic which is lighter weight than normal plastic. These lenses are ideal for glasses which made for children and teenagers as well as sports glasses, they have ability to block UV rays by its shatter resistant. Standard polycarbonate lenses with an Abbe value of 30, this very low Abbe value, make polycarbonate as the excellent selection to produce rimless eyeglasses.
High- index plastic lenses are used to produce thinner lenses. As a result of increase in density vs. mid- and normal index materials, these lenses are not lighter, like other plastic lenses. These lenses are typically thiourethanes, along with sulfur atoms in the polymer, which creates high level of refractive index. Strength and shatter resistance quality consists with High-index Plastic lenses make them particularly suitable to produce rimless eyeglasses. These lenses suffer from much higher level of chromatic aberration, which makes its Abbe value to very low.
Photo Chromic Lenses, able to change from dark outside to light inside, which make excellent choice for the light-sensitive person who frequently spend large amount of time in and out if the sun. Photo chromic lenses, are eyeglass lenses which darken automatically when exposed to sunlight and fade back when wearer return indoors. Photo chromic lenses are nearly clear in indoors, darken to medium sunlight and tint in outdoors. These lenses provide the most convenient protection against UV radiation compare to other lenses.
The most famous type of high-detention eyeglasses referred as ‘free-form lenses’. Free-form lenses also called as digital high definition lenses. These frames are specially designed to provide sharper vision in all conditions and reduce glare for nighttime driving. Free-form lenses, which combined with certain digital fabrication, to provide the sharpest vision possible and most accurate lens power to the eyeglass wearer.
An anti-reflective coating support to reduce the reflections and make the wearer’s lenses much clear vision to see through and constant eye fatigue and eye strain. Apart to that, anti-reflective coatings are hydrophobic (water repelling) and make the fog up less easily. Presently number of computer users feel comfort of improves contrast and less harsh glare through anti-reflective coating. Eyeglass lenses combined with anti-reflection coatings able to virtually eliminate distracting reflections off the lens surfaces and improve the cosmetic appearance of the eyeglass by making thick lenses look thinner.
Lightweight lens materials, such as; plastic, polycarbonate and high-index plastics, requires Scratch-resistant coating to be applied to both sides of the lens, as they have relatively soft surface. As a result of natural hardness which consists, in glass lenses, make no need of applying scratch-resistant coatings. Glass lenses are more scratch-resistant, when compared to lightweight lenses with scratch-resistant coating applied. J.A. Wimalassoriya Opticians offers you lightweight lenses include with scratch-resistant coating according to your individual prescription.
It is possible to prevent UV rays from reaching wearer’s eyes, by applying the Ultraviolet treatment, without changing the colours of the lenses. Due to that there is no need of clear lenses, which provide additional protection from UV lights. Eyeglasses and lenses with UV coating applied definitely provide 100% UV protection to the eye wearer. Ultraviolet treatment also reduces the risk of some eye strains and disorders due to the formation of cataracts and macular degeneration. But there is no necessity to apply UV coating to either polycarbonate or high-index plastic lenses, as they block 100% UV ray themselves.
Presently wide range of natural colours are applied to eyeglass lenses. Specialized tints are designed for outdoor activities, like shooting and racing. There are also available certain comfort tints for night time driving. People who suffer with dyslexia also can tinted there lenses in various colours, as it helps them for their reading. In J.A. Wimalasooriya Opticians you are free to choose your tint which suits your prescription lens package you wish to have.