Sunglasses |
We offer a wide range of sunglasses, from value for money ranges to the latest designer brands, whether they be bespoke to your prescription or non-prescription.
We can advise you on the correct sun protection whatever the conditions.
Beach wear
Street wear
Ski wear
Driving
Mountaineering
Sailing
Brands include Chanel, Rayban, Gucci, Oakley and many more.
There are Three Types of Sunglasses.
1. Cosmetic spectacles that do not give significant protection
against the sun and are worn as fashion accessories
2. General purpose sunglasses for reducing glare in bright light
or in circumstances such as driving in daylight.
3. Special purpose sunglasses for activities such as skiing or for
people abnormally sensitive to glare.
 Sunglasses give comfort in
very bright conditions by
reducing the total amount
of light reaching the eye and,
in particular, protect the eye
from the damaging
ultra-violet
(UV) part of the
spectrum.
There are two types
of UV
- UVB and UVA.
UVB is radiation within a wavelength
of 280nm to 315nm
(nm = nanometre, which is one
millionth
of
a millimetre!)
This radiation is
substantially absorbed
at the
surface of the cornea but can
reach the retina. Excessive exposure
can cause permanent
damage to the cornea and conjunctiva, but this may not
progress if further exposure is avoided.
UVA (315nm - 380nm) radiation penetrates more deeply
and can cause damage to the crystalline lens and retina.
Permanent effects such as cataract development are seen
as accelerations of the ageing process.
Which to Choose?
Always look for BS 2724. This British Standard sets
performance levels for quality, strength, stability, design
and manufacture as well as the amount of UV they let
through. Purchasing sunglasses that don't conform to
this standard is not advised.
Non UV absorbing lenses can do more harm than not
wearing anything at all. Behind a tinted lens, the pupil
opens wider allowing in more UV light than would happen
normally and thus reduces the eyes' natural protection.
Sunglasses sold under BS 2724 have a "shade number".
Shade numbers relate to the amount of UV allowed through.
The higher the number, the better the protection.
| Filter Category |
Visible Light Transmission |
Description |
Usage |
Restrictions |
| 0 |
100 - 81% |
Clear or Very Light Tint |
Comfort
Indoors
Cosmetic |
None |
| 1 |
80 - 44% |
Light Tint |
Low sunlight |
Not suitable for night driving |
| 2 |
43 - 19 % |
Medium Tint |
Medium sunlight |
Not suitable for night driving |
| 3 |
18 - 9 % |
Dark Tint |
Bright Sunlight |
Not suitable for night driving, may not be suitable for any driving |
| 4 |
8 - 3 % |
Very Dark Tint |
Very Bright Sunlight |
Not suitable for any driving |
Usage Restrictions
Lenses are deemed unsuitable for driving if light transmission is less than 8%, or if the tint affects perception and recognition of traffic lights. For night driving, transmission should not be less than 80%.
Does the Colour of the Lens make a Difference?
Brown and grey are the most popular colours and green is one
of the most effective. However, it is the "shade number" that
counts.
Safety
For safety, choose plastic, toughened glass or laminated glass
lenses. Check sunglass lenses by holding them at arm's
length and looking through each separately at a vertical line.
If the line distorts or wavers when the lens is rotated slightly,
the lens is imperfect.
Are There Such Things as "Sun Contact Lenses"?
Yes. This area is developing quickly. Ask your contact lens
practitioner about the latest products available. Sports people
involved in open air activities may find these particularly
interesting.
What about Prescription Lenses?
Both sunglasses and contact lenses are available to your
normal optical prescription. Your practitioner will be pleased to advise you and will ensure that you have UV protection built in.
Which Sunglasses are Best for Driving?
The Highway Code states that tinted glasses should not be
worn at night or in poor visibility. Sunglasses should not be
used at night to stop head lamp glare. They should also be
removed if driving from bright sun into a tunnel. Don't pick
a very dark tint. A medium density is normally sufficient
and it is safer as it transmits more light.
Graduated Tints
These are tinted darker at
the top than
at the bottom
and give useful protection
from bright overhead light,
leaving a
lighter area for
map reading or seeing
the
dashboard.
Photochromic Lenses
These lenses darken on exposure to sunlight and should react efficiently in changing light conditions. They should not leave much tint present when the lens is not exposed to the sun.
Polarising Lenses
These lenses reduce reflections from wet or polished road
surfaces, but they reveal the stress patterns in older types
of toughened windscreens, which can be hazardous. They are also useful for cutting glare from water surfaces, for example when fishing or sailing.
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