RX Prescription Lenses

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Bigatmo sunlens technology, lens material, lens design and finishing technology, combined with the expertise of our finishing lab, enable us to produce outstanding prescription sunglasses.

Every pair of Bigatmo RX prescription sunglasses starts with a pair of semi finished lens-blanks. The front surface of the lens-blank is the finished part and carries all the sunlens filter technology in the first 0.9 mm. This ensures that our prescription lenses have the same sun-filters as the Alutra, Zeolite and Zeolite Polarized non-prescription lenses.

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Exceptional optical clarity

Our lenses are cast from NXT/Trivex ® in glass moulds and cure very slowly in a temperature controlled environment, resulting in very low internal stresses and excellent optical properties. Every lens material deforms slightly during the manufacturing process due to the pressure of the cutting tools on the lens surface, but NXT/Trivex ® has excellent mechanical properties with practically no deformation and this contributes to a more accurate prescription lens.

Applying a prescription to a lens is a complex multi stage process that takes place at our “finishing” labs. This is when your prescription is “generated”  and polished onto the back of the lenses, coatings are applied, the lenses cut and edged and finally fitted into their frames.

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More accurate prescriptions

Over recent years incredible advances have been made in the design and manufacture of prescription lenses. Until quite recently applying a prescription to a wrapped, curved lens was a tricky process which few labs tried and even fewer attained acceptable results. Digital Freeform lens generating and polishing technology changed all that, allowing different kinds of prescription to be placed on the back of the lens using computer controlled machinery.

A little while ago the best machinery would generate prescriptions using about 5,000 co-ordinates – now our lenses are prepared using in excess of 40,000. All Bigatmo’s RX prescription sunglasses – both single vision and progressive – are produced using the latest generation Digital Freeform systems.

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Lens designs to suit your lifestyle

In broad terms, the surface of a varifocal (or progressive) lens is divided into three areas. The top part is for viewing distant objects, the bottom part is for reading and close work and the part in-between handles the focal lengths between reading and distance – an instrument panel for example. The intermediate area is particularly important when driving or flying and so a lens which is natural to use is a real advantage. The idea is that the areas blend into each other thereby replicating natural vision.

In order to take advantage of Digital Freeform and NXT/Trivex ® technology you also need excellent lens designs and you won’t be totally surprised to hear that there companies that specialise in producing digital lens designs to suit individual lifestyles.

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Natural varifocals with excellent intermediate vision

At Bigatmo we considered many lens designs and trialled a short list before choosing the Freeway design as our standard. Freeway was designed by some extremely clever people as a driving lens as it has a particularly versatile intermediate area.

Another reason for choosing this design is that it’s quite easy to adapt to and our customers often tell us how natural that it is to use. We have very high success rates with this design but it’s worth remembering that, if you haven’t used varifocals before, some people have to persevere for a while until they get used to them. Think of this as your brain adapting to the new way that data is presented by your eyes.

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Eye tests, fittings and measurements

To benefit from all this amazing technology, it is crucial to supply precise information. We prefer our customers to visit their optometrist for a fresh eye test and it’s also very important that the dispensing optician ensures that the sunglasses are correctly fitted and that comprehensive measurements are taken, no matter what prescription is required.

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Prescription ranges and bespoke solutions

Our typical range is +/- 3.5 D. Depending on the eye shape you have chosen we may be able to increase this range – just contact us to discuss your needs.

We can also produce bespoke solutions. For example, we created bespoke varifocal sunglasses for a glider pilot. Glider pilots need a larger area for distance vision and smaller areas for intermediate and near vision. This lens design has become our standard and a popular choice amongst the gliding community.

Like our glider pilot, if you want something different, special, or that you just can’t find in high street stores, please contact us to discuss your needs and how we might be able to help.

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