Spectacle Technology

Zeiss sunglasses photograph

Spectacles are not new. They have been around in various forms for several hundred years. In the past the frames have been made out of a variety of mainly natural materials such as horn, wood, tortoiseshell, silver and gold. The first lenses were made of a natural crystal and then later were made of ground glass.

Today's technology enables us to provide much more sophisticated eyewear that has wonderful optical qualities and is comfortable to wear. Frames are now made from various materials. Metal frames can be made from Titanium, an extremely strong metal that is durable and keeps it's looks well for years. It is also one of the lightest metals and can be used for the mounts and sides that make up the very lightest option in spectacle wear. Titanium is also hypo-allergenic as is Stainless steel. Stainless steel makes a very strong frame , not quite as light as titanium but it is generally a little cheaper. Budget metal frames are usually made from a nickel alloy. If you have any allergies always let your optician know and they can the guide you to the best option.

Spectacle lenses are now made from a variety of plastics and glass materials. In general glass will be heavier but thinner than plastic which is much lighter and safer.

Most lenses nowadays are made of optical quality plastic. The reason for this is that they can be made in very complicated optical designs that would be prohibitively expensive if made in glass. They are also more comfortable to wear and are extremely safe when compared to glass.

Single vision lenses are the normal ones chosen for reading or distance glasses.

Bifocals combine two focal lengths in one lens and are typically used for distance and near vision in one pair of spectacles.

Varifocal (progressive) lenses allow clear vision at all distances as the prescription is gradually blended from distance to near.

Office lenses are a new addition to the lens types suitable for a variety of visual needs created by a modern office environment. They are mainly focussed for near vision but blend towards the top of the lens so that you can see across a room.

Anti-reflection coatings can be applied to most lenses and give several enhancements to how a lens looks and performs. Firstly it makes a lens clearer by allowing a smoother passage of light through the lens. Secondly it reduces glare for instance with headlights driving at night or from computer screens. Thirdly it enhances ocular comfort.

The cosmetic appearance of your final spectacle lens will depend upon many factors. And you must ask your dispenser or optical assistant to guide you and explain what would be best for your needs.

Zeiss sunglasses photograph

Tinted lenses or filters can be very useful in a variety of conditions. The eye itself can cope with a huge range of differing lighting conditions but at times it is beneficial to give it some help. The most obvious situation is in bright sunshine when most of us are helped with a general sunglass filter. Sunshine gives us "visible" glare but it is the "invisible" glare that can be more harmful, particularly Ultra Violet radiation which is high energy short wave radiation that penetrates the earth's atmosphere and clouds. It is therefore important to make sure that if you have tinted spectacles that they also block U.V. radiation. All Bill & Taylor lenses will do that.

Photochromic lenses are the ones that darken when you go outdoors and come back lighter when indoors. These are good general purpose tinted lenses. The original lenses were only available in glass but over the past years the technology has been incorporated into plastic lenses and the main type now is called Transitions. These have been improved and we only use the latest version unlike some opticians who will use older cheaper technology.

Polarising lenses are helpful where there is a lot of reflected glare such as on the beach or sailing when light is reflected off the water as well as being direct from the sun.

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