|
GEORGE CLOONEY
WITH SUNGLASSES
THE HIGH INDEX LENS
IS THE THINNER RIGHT LENS
TINTS CAN NOW BE
MADE TO VIRTUALLY ANY COLOUR
LIZ HURLEY IN SUNGLASSES
THE LEFT LENS HAS AN ANTI-REFLECTION COATING
CALVIN KLEIN SUNGLASSES
THE HARRY POTTER LENS
A PAIR OF JOHN LENNON'S SPECTACLES
NEXT GENERATION TRANSITIONS ARE NEW PHOTOCHROMIC LENSES WHICH GO FROM CLEAR TO DARK
IN 30 SECONDS
CLEAR IS SEEN ABOVE AND DARK BELOW
SUNGLASSES FROM MARCHON FOR 2003
SUE BARKER
WEARING RODENSTOCK SUNGLASSES
|
WHAT ARE LENSES MADE OF?
Most people (96%, according to one lens supplier) choose plastic (organic CR39) lenses these days as they are half the weight of glass and less likely to break. If the plastic lens breaks it forms smooth edges and does not produce sharp splinters which can enter the eye. Where extra toughness is required polycarbonate lenses are the lens of choice and are suitable for most sports and steam up less than the other materials. The drawback of being more easily scratched is overcome to a great extent by the application of anti-scratch coatings. According to one large UK optical supplier, single vision lenses account for 68% of all lens types, 17% progressive (varifocal) lenses and 13% bifocals.
CAN I HAVE THINNER LENSES?
Thinner lenses are available now for everyone and are advisable particularly for patients with strong prescriptions. The use of high index materials can reduce the edge or centre thickness of the spectacle lenses and thus improve the cosmetic appearance. It is usually better to have an anti-reflection coat as well as the denser materials tend to reflect light more.
A PARTIAL ANTI-REFLECTION COATING TO DEMONSTRATE THE EFFECT
|
WHAT IS AN ANTI-REFLECTION COAT?
An anti-reflection coat is an almost invisible film applied to the surfaces of spectacle lenses to reduce those annoying reflections from the surfaces. The thickness of each layer of a multilayer anti-reflection coat is 1/1000th the thickness of a human hair. An anti-reflection coating not only improves the appearance of the spectacles as well as enhancing the wearers looks, it actually enables you to see better by eliminating the unwanted reflections which may be particularly noticeable when driving at night. White lenses are those which transmit more than 99% of light. Some high index lenses can look tinted even from the surface reflections. Lenses of refractive index of 1.5 reflect 4% from each lens surface while lenses of refractive index of 1.9 reflect 9% from each lens surface. An anti-reflection coating allows more light through but cuts out reflections when the light source is behind the wearer such as if the sun is behind the wearer.
WHAT
ARE PROGRESSIVE LENSES?
Progressive
lenses are lenses which have your distance correction at the top and as you look down the lens progressively nearer objects come into focus due to the progressive change in lens power. Progressive lenses used to be called varifocal, varilux, progressive power lenses and progressive addition lenses. Today there is a huge range of progressive lenses but the best progressive lens is the Rodenstock Impression ILT progressive spectacle lens. D & J Brower Opticians are qualified specialist advisers on the Rodenstock Impression ILT progressive spectacle lens – the first progressive lens to be individually designed for you.
For computer users the Office lens not only corrects vision but allows for correct head and body posture when viewing through the correct zone of the lens. This lens is suitable for all age groups providing the prescription is within the range available. It is untrue that VDU screens emit harmful UV radiation though like anything warm they do give out a bit of IR.
ARE YOU HAVING TROUBLE TRYING TO GET USED TO YOUR PROGRESSIVE LENSES?
The easiest way to get used to progressive lenses is to switch to the lens which is the easiest to get used to — the Rodenstock Impression ILT progressive spectacle lens. If you are having trouble getting used to your new progressive lenses try the following.
The upper part of the lens is used for long distance seeing so simply move your head to face the object you wish to look at and drop your chin slightly if things look blurred.
The middle part of the lens is used for middle distances at around arm's length. Just point your nose at what you want to see and raise your chin slightly to ensure you are looking through the right part of the lens.
The lower part of the lens is used for near vision such as for reading print. Raise your chin and look through the lower part of the lens.
If you find something is out of focus just point your nose at it and move your head up and down slowly until things come into focus.
|
|
LENSES FOR THE SUN
D & J Brower Opticians offer a wide range of optical quality sunglasses designed to provide comfort in bright light and protection from glare and hazardous ultraviolet (UV) rays. Contact lenses that block up to 90% of UV rays are also available. All tints dispensed as prescription sunglasses should conform to BS EN 1836 (1998) for UV, visible and IR (infra-red) transmittance. This standard allows a significant proportion of UVA to be transmitted and some UVB. All tints other than grey neutral density filters distort colour vision to some extent
D & J Brower Opticians stock a wide selection of sunglasses all year round, including the Reflections Sunglasses Range at £29.95 without a prescription and at £59.95 to most prescriptions and the Calvin Klein designer range of sunglasses. At D & J Brower we will ensure that your sunglasses will be properly adjusted to fit correctly for you.
Our eyes are not designed with sufficient natural defences to deal with the hazards from exposure to ultra violet (UV) rays from the sun's radiation and our eyes are at greater risk due to the depletion of the ozone layer. Excessive exposure can lead to Sand, concrete and snow tend to reflect substantial amounts of ultraviolet and hence increase the risk of damage to the eye. Protection is essential for skiing or water sports as well as just sitting on the beach or by anything that can reflective. Reading in direct sunlight is approximately 1000 times brighter than in normal artificial lighting.
Wearing a broad-brimmed hat or peaked cap can considerably reduce the amount of glare and UV but properly prescribed protective lenses are far safer. All sunglasses and tinted prescription lenses should meet the British Standard for sunglasses (BS EN 1836:1997 and its companion EN 172 or BS 2724:1987): category 2 (20% transmittance). The ANSI Standards for Class 2 UV blockers allows a maximum transmittance of 30% for UVA and 5% for UVB. Because water vapour does not absorb UV light it is worth remembering that considerable amounts of ultraviolet light is able to reach the earth's surface on quite cloudy days in the summer.
Most parents do not realise that children are especially at risk because they can spend a long time outdoors on sunny days without any eye protection. Some ophthalmologists even recommend children to protect their eyes from the sun's harmful rays by the wearing of sunglasses whenever they go out because of the long term risk of developing cataracts.
WHY ARE ULTRA VIOLET (UV) ABSORBING SUNGLASS LENSES IMPORTANT?
Normally the sun causes the pupil to constrict or get smaller but sunglasses lenses cause the pupil to dilate or enlarge and therefore more harmful ultra violet rays pass into the eye.
|
|
THE HISTORY OF SPECTACLES
FIRST SPECTACLES
It is not known who invented the first pair of spectacles nor when but most experts agree that an Italian glass worker made the first pair of spectacles around 1260. The first description of spectacles in England is attributed to Roger Bacon in 1267 and the earliest known portrait of spectacles being worn was painted by Thommaso da Modena at Treviso in 1352 and is shown below.
The oldest pair of spectacles (depicted below) was found in England in 1974 by the riverside in Trig Lane, London EC4 and has been dated to 1440 and are made from the bone from the front leg of a bull and rivetted together. The earliest spectacle maker in England was Paul van de Bessen of "Suthwerk" around 1458 and the first English spectacle maker was Spyke Dowd in 1485.
FIRST LENSES
There are lenses which have been dated to before 2000 BC although the Nineveh lens, which is in the British Museum, dates back to the 7th century BC. Aristophanes (257-180 BC) in his play "Comedy of the Clouds" refers to a burning glass and Pliny (23-79 AD) describes the Emperor Nero using burning glasses to view gladiatorial contests.
PAINTING BY ZOFFANY OF A MAN HOLDING A SPECTACLE LENS
CLOSE-UP OF THE LENS
MASS PRODUCTION
In 1384, over 1000 pairs of spectacles were imported through the Port of London and by 1629, spectacles in France and Germany were being mass produced. The cost at this time was 1d (one old penny) for a pair of leather spectacles.
17th CENTURY
On June 9th 1628 there was a "Humble Petition of Robert Alt on behalf of himself and other poore Spectacle Makers in and about the Citie of London for a Charter of Corporation".
On 16th May 1629, the Worshipful Company of Spectacle Makers was granted its Charter by King Charles 11 to control the import and supply of spectacles. All the records of the Worshipful Company of Spectacle Makers, except the Charter and the book of ordinances, were destroyed in the great fire of London but from then on details are available. The cost of spectacles in the late 17th century ranged from five shillings to 2s 1d.
LOW VISION PATIENTS
Low vision patients can benefit from the use of tinted overspecs, which are designed to fit over your own spectacles and provide protection from visible and ultra-violet light. They have wide side-shields and a top ridge to prevent light entry from all angles.
There is a very large range available, including clip-on and sunglass styles. Please advise us of your requirements.
|
