How To Choose the Right Glasses Frame?
From a pure utility point of view, the frame is nothing more than a device for fixing lenses. Its task is to ensure the correct position of the lenses in front of the eyes. The idea is the position in which the middle line of the light apertures (the light aperture is the space bounded by the rim of the frame) passes approximately through the centers of the pupils or somewhat lower.
Optimally, when the back surface of the lenses is at 12 mm from the top of the cornea. The only exceptions are the so-called half-glasses, which make it easier to look from far distances (over the glasses) to near ones (through the glasses). In practice, the fit of the frame often results in a slightly elevated position of the pupil relative to the midline of the aperture. It is recommended to shop glasses frames from a reliable vendor as your eyes well-being depend on it.
The frame consists of two main parts, namely the frame, which provides fixation of the lenses, and the temples, which provide the specified position of the glasses. The light openings of the frame limited by the rim are interconnected by the so-called bridge, or bridge, or bridge of the nose – the nose of the frame. Considering that the maximum weight of the finished glasses is exactly on the bridge of the wearer’s nose, it is important that the frame provides the greatest fit of the glasses in this part, and that the weight is evenly distributed. Most metal frames are additionally equipped with movable adjustable nose pads, usually made of silicone or rubber, to better fix them on the face. Specialists in the production of plastic frames successfully solve the problem of fixing and distributing the weight of finished glasses due to the design of the frame itself
From the choice of material from which the spectacle frame is made, its appearance, weight, service life, as well as some other characteristics largely depend. The main materials to produce spectacle frames are plastics and metals.
Types of plastics used to make frames:
- Cellulose ethers. Among plastics, cellulose acetate remains the most popular. Today, the optical market presents both frames made of milled multi-layer cellulose acetate, and eternally fashionable blck glasses. In addition to cellulose acetate, cellulose propionate is also widely used – mainly for molded frames.
- Polyamides. Depending on the manufacturer, these types of plastics have certain names. Grilamid is one of the most popular plastics today. Polyamides are often used to make sports eyewear, as their main characteristics include flexibility and strength.
- Optil and other materials based on epoxy resins. Optil – a material created based on epoxy resins; it is 20% lighter than acetate. This type of plastic is also used to make sports glasses. In addition, it has outstanding decorative properties, as it allows you to include “alien” elements – pieces of fabric, metal, etc.
- Metal frames.
Types of metals used to make frames:
- Steel. Among metal frames, stainless steel frames are becoming more common. Frame manufacturers value its properties such as corrosion resistance, hypoallergenic, flexibility, lightness, and durability. Its wider distribution in spectacle optics is hindered by a rather high cost; in addition, steel becomes brittle when exposed to high temperatures.
- Aluminum. Currently, the number of products from various aluminum alloys is increasing. This material is 3 times lighter than steel and 2 times lighter than titanium. Aluminum alloy sheets can be used to make milled frames that are resistant to corrosion. Today, aluminum is considered one of the most promising materials for spectacle optics – it is as strong and corrosion resistant as cupronickel, and at the same time much lighter.