Learn more about mineral glass for prescription glasses
It's no secret that corrective glasses consist of a frame and corrective lenses. These can be made from different materials: organic glass, polycarbonate or mineral glass. Every material has its own characteristics. To better understand the strengths of mineral glass, here is a brief overview of its properties.
A precise manufacturing process
To get corrective glasses, you must first contact your ophthalmologist. This will create a recipe that will indicate the corrections that will suit you. You will then need to consult an optician who will assist you in choosing the material for your lenses and will determine the centering of the lens in the selected frame. This information is attached to the prescription from the manufacturer who starts creating the lens.
Glass has been used in optics for a very long time. The first glasses were made with "glass" lenses as early as the 13th century. This component consists of sand and many organic elements. So we find quartz - about 70% -, potash and lime - 20% - and oxides - 10% - which are used to harden the material. Lead and titanium can appear in the list of components. Their function is to increase the index of refraction. Lenses that need to be coloured for increased visual comfort may contain other elements, such as cobalt, to achieve a blue hue.
These different elements are melted at a temperature of 1500 ° in a special so-called glazing tank. The mixture is then stirred for many hours to create a paste - the liquid glass. This material is then passed through a press whose job it is to flatten it. This is the first step in getting an initial draft of the eyeglass lens called a puck. Then comes the creation of the glasses themselves. Depending on the needs of the person who ordered the glasses, two techniques are available.
The glass is processed with the so-called freeform technique for corrective glasses. It can also be moulded. This technique, known as standard glass, is ideal for simple glasses. This second technique is faster because it is not personalized. It is ideal for a standard correction.
Once the technique has been selected, the manufacturers proceed through 6 steps to create the lens for your prescription glasses. They work on half-finished pucks that have already been corrected on the outside in order to adapt them perfectly to the recipe. Then comes the slippage, which consists of applying protection to the face of the glass. The glass can then go through roughing. Then the specialist gives the lens - depending on the frame - the desired shape and provides the necessary details. Now is the time to polish the glass. The glass is almost ready. You need to remove the protective layer - the slide - and then clean the surface. The desired treatments - for example anti-scratches - are then applied. The lenses are then ready and can be placed on the frame.
The production of glasses from "real glass" remains more difficult. Indeed, glass cannot be mass produced. Abrasive techniques - for applying surfaces - require special machines in particular, and today many opticians only offer this material for certain corrections.
A material that can be changed as needed
Your eyesight can be corrected with glasses. They are then called eyeglasses. They are therefore crucial. We have already seen that glasses are made according to a prescription. If your vision professional and optician have decided that mineral lenses are right for you, it is because the lens is a perfect match for your visual defect and the benefits you want.
Glass, like other materials used, has its own parameters, but these can be adjusted to improve performance. For example, it is possible to reduce the thickness of the glass in order to modify its refractive index as precisely as possible. Refraction is the change in direction of light rays passing through glass, or simply the intensity of the deviation of matter. The refractive index depends on the desired correction. With hyperopia, convergent refraction is required. To correct for myopia, a diverging index of refraction should be used. A high index of refraction is equivalent to a thin lens, regardless of the correction applied.
Since the lens can be changed continuously, it is ideal for all types of corrections. It can therefore be concave to correct the defects associated with myopia. This feature improves visibility from a distance. The centre of the glass is thin in the middle and the edges are thicker. Conversely, the glass must be cut along a convex plane in order to enlarge the close-up images. This is also the technique used for magnifying glasses. The axes and orientation of the lenses have yet to be changed to improve the vision of people with astigmatism.
For presbyopes, varifocal lenses are manufactured according to three plans. A thin area at the top for improved distance vision, a thicker area at the bottom for near vision, and in the centre a medium distance area that provides a high quality intermediate vision.
Mineral glass glasses can therefore be produced endlessly and adapt to every need and budget. In fact, there are three categories of “ready-to-wear” glass that are mass-produced with customized glasses.
The advantages of mineral glass
Even if mineral glass can be perfectly adapted to every need, nowadays it is used less and less in favour of bio-glass. The fact remains that in some cases it is still preferred and has many advantages.
Thus this material has a wide range of indices of refraction from 1.5 to 1.9. It can then be used for all corrections and especially adapted to strong corrections, which is not the case with polycarbonate. This advantage makes it possible to equip frames with thinner and therefore lighter glasses than with an organic model. This feature allows you to choose the frame you want without worrying about the thickness of the lens.
This material is also ideal for making high quality bifocal or trifocal lenses. It distributes the colours much less and thus offers greater visual comfort, even if the glass is thick. Chromatic dispersion is a problem that many eyeglass wearers encounter with other materials. The light rays are broken down by the different glass thicknesses and form a prism that is visible to the user. With mineral glass this problem is eliminated even with a high refractive index.
These "glass lenses" can be spherical, toric, or even aspherical, which allows any visual errors to be corrected.
Glass is made of durable materials - quartz in lead. It retains this solidity even during transformation. It won't get scratched, so it will last longer without being damaged. However, it remains fragile and can break in the event of an impact. Because of this, it is not recommended for children.
The glass is compatible with a wide variety of treatments. We can therefore add an anti-reflective or photochromic layer to improve visual comfort in strong light without having to change glasses. If you want mineral lenses, you know that they give you great comfort but remain heavy. They are not recommended if you are doing any activity that may cause shock. Conversely, they are recommended if you are working in a dusty environment as they are very resistant to abrasion. To get to know this material again, it can be adapted to a wide range of frames, but is not suitable for Nylor models - with metal wire - and holes.
A quality lens for your frames
Any good optician can offer you mineral lenses if your vision calls for it. Visionet offers you mineral glasses from a recognized manufacturer. You can equip your frame with parts that are perfectly tailored to your eyesight and receive the treatment you want.
Since these lenses are quite heavy - even if they are thin - it is best to choose a suitable frame, neither too heavy nor too big, so as not to add weight.
Edge frames are the preferred ally of mineral lenses. These models, which are often reserved for strong myopias, bring a very vintage touch and are very trendy. Just take a look at the Gucci GG-0297-OK - 001 or the very chic DiorStellaireO4 - DDB to see for yourself.
If you need to buy bifocal lenses to correct your presbyopia, tall frames are recommended. Indeed, they allow for a clear view of near and far. Butterfly frames are ideal as they perfectly cover the eye. And the choice is huge. Fashionistas will appreciate the very current and original Dolce & Gabbana DG-5025 - 3133. The smarter can take over the Kenzo KZ-2236-02. Men will protect their eyes behind very elegant frames like the Pierre Cardin PC8444-. 807 or more original Maritza M-0185 - BLJ.
