Lens shift in customer’s glasses
You have come back from a resort. You are relaxed and happy. But suddenly you find out that your new glasses are out of order. There is a deep scrape in the center of the lens (where from?), or lens’ edge has grown muddy under the influence of salt water, or your favourite glasses have become twisted or covered with a net of scrapes because of the heat. Don’t get upset and don’t put the blame on yourself for carelessness. Lenses can almost always be substituted for similar or better quality ones at a very reasonable price.
LENS SHIFT IN SUNPROTECTIVE GLASSES (in a frame see below)
If you have scrapes, layering, attrition or white dots, your carefully considered image goes up in smoke. It’isn’t a disaster. A good optic workshop is able to reconstruct practically the same convenient for you color combination and even strasses pattern. The image found by you in the Internet can be reconstructed and made more up-to-date due to a new color combination. And fitting mirrorlike lenses will completely change your appearance. You are very likely to give color patterns to the contractor while choosing the lens.
In the context of utility, if you want to have a new brand of sunprotective glasses, you can fit a highly specialized lens into your favourite old frame. For example, a Driver or a Blue Blocker for driving, a Polaroid for fishing or a bright color creating an image for a glamorous going out at night. If your glasses look conservative, you can turn them from a beach brand into a universal city one by fitting a photochrome lens or by transparent cosmetic tinting. Even if you have a substandard brand which can have only an original lens shift, there is a low-budget way out: to fit the lenses from another pair of sunprotective glasses.
There are two main points in sunprotective glasses lens shift. They are the curvature and the type of fastening.
STANDARD BASE (CURVATURE)
There is no problem if the curve of the frame is standard and its curvature coincides with the “zero” lens without a diopter (usually base is from 4 to 5) in stock. You can have any color, level of darkening and low price. Screw-fastened and metal line samples are exceptions. They need lenses from stronger materials on the basis of utility. By the way, you can always send a photo of your glasses taken at different angles by Viber, Telegram, WhatsApp or e-mail and get advice about the possibility and price of the shift.
If your glasses have an extended curve, high curvature (base) lenses are a necessity. You can also possibly need a lens of a definite width or an extended diameter because of the peculiarities of fastening. After taking necessary measures the order is manufactured at a factory. Therefore, the production time is much longer and the price is much higher in comparison with the lenses in stock. But there is a good alternative. Polarised lenses, which are initially high curvature ones, can be fitted. However, in this case you have to choose from available colors.
Sometimes it is possible to order original lenses from a manufacturer, but the delivery date is undetermined and the price is quite substantial. There is low probability of a monolens shift. In such a case, the lens is the main part of the glasses and, accordingly, of the price. If a mineral lens is damaged (even hardened glass is easy to be broken and chipped), it is better to shift both lenses to lighter and safer polymeric ones. It is hard if not possible to find a quality mineral lens.
ONE OF THE FAQS IS PROTECTION FROM ULTRAVIOLET
Manufacturers use materials which are agreeable with the requirements of protection from the most dangerous extreme ultraviolet. Further processing just increases the protection level. Lenses are more likely to differ in optical qualities: presence of distortions (chromatic and optical aberrations), strength and durability, color rendering and temperature resistance, transmitting the blue part of the visible spectrum. The requirements to the materials opticians work with are much tougher than the requirements to sunprotective glasses. Choose your own appearance and image and quality will be guaranteed.
WHAT TYPES OF LENSES DO SUNPROTECTIVE GLASSES HAVE
This is the most frequently used material for sunprotective glasses. It has low prime cost. It is high-test. It holds UV rays without extra filters. But optical characteristics worsen because of the slightest irregularities in manufacturing process. That is why, there are often choppings off and splits in cheap sunprotective glasses, color and space geometry distortions are possible. Materials can lose their transparence under the influence of high temperature (it can be higher than 80°C on the dashboard of your car). Polycarbonate is also easily damaged by different solvents.
Polarized lenses consist of several layers of thin polymeric material. In most cases polarization film is between the two layers of strong but flexible grilamid. Polarized lenses not only take away flares but also visions from some liquid-crystal panels. They can also discover hardened zones and defects represented by off-white spots on the optical glass. The main practical drawbacks of polarized lenses are low abrasion resistance and the possibility of layering with sharp variations in temperature or affected by different cosmetics.
The so-called “white” polymeric material is fitted only into the most expensive brands of sunprotective glasses. It has high optical quality, stands the impact of numerous solvents and high temperature undamaged. It makes possible to have complicated multicomponent color of tinting. This very material is usually used while making lens shift in sunprotective glasses. Moreover, the hardness of the surface improves and the lifespan becomes longer if brand chemical agents are used while coloring. Low strength is a disadvantage.
LENS SHIFT IN THE CUSTOMER’S FRAME
Nothing lasts forever. Sooner or later any lens falls into disrepair despite the caring attitude towards it. Daily used quality lenses don’t usually lose their characteristics for about three years. Lens shift is absolutely necessary if there are scrtatches, choppings off, splits, thermal damage, a new prescription.
THE PRESCRIPTION IS LOST: WHAT IS TO BE DONE?
Every workshop’s equipment includes a dioptrimeter. Having it and your glasses the prescription can be reconstructed. But in the case of astigmatism it’s better not to lose the prescription, as during the time of use guiding axes can change their position. It is impossible to fit a diopter if the lens is severely scratched in the center or completely broken.
Yes, if it is provided for by the operation manual. The shift is impossible if lenses were moulded together with the front piece. Ready-made metal glasses can be solid, whereas plastic glasses can be made of not subjected to heating hard materials. In this case, the risk of breaking the glass or the frame during the process of lens shift is very high. Nevertheless, it is possible, though the lens will have some looseness (will play a little while being cleaned).
The front piece is subjected to heavy mechanical stresses when you fit lenses into a plastic frame. That is why, if there are symptoms of plastic’s aging (flares inside the material, fogging of the material, microcracks), the technician will refuse fitting. If new lenses have been fit into such a frame, it is likely to break in the coming months.
Yes, if you have the order-form to define the brand and the second lens is perfect-conditioned. Lenses of quite different characteristics can’t be fitted as it can lead to ocular discomfort. It’s not worth shifting one photochrome lens, because the operating speed and the level of darkening change in the course of work. It is very problematic to shift one lens if it is screw or plug fastened as they are manufactured paired using the technology. In any case, some differences are probable if you shift one lens, because it is impossible to reconstruct the previously used machine settings.
It is quite rarely possible. And you need to have a prescription. The price of the manual fitting of the lens shape is many times as high as that of a standard technological process. The old lens’ usage is reasonable if you have a practically identical frame, or the prescription is very unusual, and the lenses’ cost is so high that it is worth making. The size of the bridge is the main problem. It should be a couple of millimeters longer in the new frame than in the old one which is difficult to manage. The way out is to have the valuable lenses screw fastened. In this case the variety of bridge sizes for keeping Pupillary Distance is much bigger.
Customers’ glasses are usually reluctantly taken by opticians and almost always “with no warranty”. Why?Problems appear because of the uncertainty about the responsible party. Opticians only follow the instructions and can’t be responsible for an outdated or mistakenly presented prescription. But center height marking and choosing the pantoscopic tilt surely depend on an optician. In most countries, even if you order new glasses, there is a conception of insurance coverage. It existed at the time of the USSR. It means that you charge the price yourself. Therefore, you evaluate the cost of work and the amount of the insurance payout in case of breakage or a disputable situation. But nowadays this logical way of solving problems is hardly probable because of the existing report system.
WHAT IS WARRANTY?
If the service was paid by you, the service provider is absolutely responsible for the quality of the ordered and paid work (but only for work). There can be sometimes exclusive experimental no-warranty orders, but this is unusual. If you paid for fitting lenses, warranty covers only the lenses fitting, not the quality of your frame and lenses. A service provider can’t be responsible for the material quality, but has responsibility for safekeeping. If the frame cracked when stripping down, it is an undetected manufacturing defect. But if the frame got lost or crumbled into small pieces while being fitted, it is the service provider’s responsibility. The idea is quite understandable: the one who got profit is responsible.
Being experienced enough we can’t see inner cracks of the frame, casting or soldering defects with all the will in the world. Think of these risks while giving your worn frame on the job. In any case, should a disagreement arise, there are certain methods for the determination of the responsible party with frequent use of expert opinion. A seller (the one who got payment for the frame) is responsible for its quality. This can be proved by a sales check, filled in form or operation manual. Taking a worn frame on a job we don’t know what kind of spectacle-case you use. We also don’t know if you can eliminate increased mechanical loadings. But we try to get as much information about these issues as possible because we want you to wear our glasses for a long time and never think of the warranty period. The work is checked with a tensiometer at our workshop. That is why, overpressure because of a too big lens is practically impossible, and your order will be made in the most delicate way.
Warranty includes full compliance with the prescription according to the all-Union State Standards, original packing showing the origin of your lenses, perfect geometry frame, especially, if you have sophisticated diopters. A good optrician also shows you all the new brands, not only the brands of the appropriate supplier, suggesting the best price/quality ratio in a well-argued manner. Never try to find an optician who takes second-hand lenses on the job with guarantee, because medical goods can’t be legally reused. We take second-hand customer’s lenses on the job only if there is a similar in price and quality supply at the market. That is why, whatever a situation can be you will be satisfied with the result.
We are always ready to meet your wishes and look for the best possible version for you.
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