SunGlass Information
Archive for the ‘Reading Sunglasses’ Category
Actually you have three choices when it comes to lens composition: Glass, Plastic or Polycarbonate. All have advantages and disadvantages we will discuss each so you can determine which is best for you.
Glass lenses provide the best scratch resistance and highest optical clarity. They are, however, 2-3 times as heavy as plastic or polycarbonate lenses and, while they are tempered for impact resistance, can shatter or break if struck by an object. These types of lenses are suitable for people who value durability and clarity but are not great for people involved in high speed sports or activities where something could strike your lenses or face.
Plastic lenses are significantly lighter than glass lenses, and thus, may be more comfortable to wear for extended periods of time. Also, while not shatterproof, these lenses are also more shatter resistant than glass. Disadvantages include average optical clarity and less scratch resistance. These types of lenses are great for customers looking for a lightweight, affordable pair of sunglasses.
Polycarbonate lenses are shatterproof and extremely lightweight. Their primary drawback is that the material is very soft and is the least scratch resistant material used. These lenses are great for active people involved in sports. Because they are lightweight they will stay put when moving around. The shatterproof lenses will also provide protection from not only UV rays, but also impact from objects or in case of an accident or a fall.
Better frames (often called Hand-Made Frames) are made from Cellulose Acetate or Zyl, as it is often called. This is the material the optical world recognizes as the finest and over 90% of it is produced in Italy by a company named Mazzuchelli or by its sister company in Hong Kong. Cellulose Acetate is derived from natural cotton and wood fibers and is subjected to a process of steaming, coloring, molding and cutting to achieve the necessary characteristics: translucency, shine, fluidity, subtlety and rich color patterns. Cellulose Acetate is used to make colors as simple as black or tortoise shell in hundreds of variations, to special colors like Lipstick Red, Lime Green or colors that change depending on the angle you see them from, and everything in between.
A Zyl frame is composed of two main parts: the front and the temples. The two parts are made separately and then assembled after each part has been completed and inspected. Creating an optical quality frame is a labor-intensive process that can be carried out only by highly trained technicians aided by technologically advanced equipment. Optical quality frames can be used for either sunglasses or fitted with prescription lenses. They are perfectly symmetrical and will not distort vision when fitted with ophthalmic lenses.
When Italian materials are used in designer frames it is made by pouring liquefied Cellulose Acetate, in colors chosen and mixed into large molds where they cool and then harden. More complex colorations are produced somewhat like a sandwich: several colors, in separate layers, and permanently bonded together. Some special colors are made up of up to 4 separate and distinct color layers. The possible color combinations of these “laminates” are endless. As the precess of making the glasses proceeds, the material is skived, or shaved away, exposing these different layers and creating stunning visual effects.
The frames are then “tumbled” with teakwood chips for as long as a week to make them smooth. The frame is then hand polished using a wax and emollient shining cream then buffed to a high luster.
A good designer spends a great amount of time designing temples that are comfortable to wear and that blend seamlessly with the front., while imparting a special flair to the glasses. Depending on the particular style, you will notice many different shapes and sizes of temples in different collection. The handmade process on the temples is as painstaking as that of the fronts because the temples are specially color designed to match he patterns on the front.
Nickel Silver wire temple cores and barrel hinges are inserted into the polished temples using an ultrasonic machine that shoots them into the temple at the proper angle. The wire core can be adjusted by you, or an optician, to comfortably fit each individual customer.
In this two-part Blog, I will discuss the three main ways that non-metal sunglass frames are made. In this part I will discuss the first two types Injection Molding and Advanced Materials. In the next part will be devoted to explaining Hand-Made frames.
The least expensive method is made by Injecting a mold created from aluminum or highly polished stainless steel with liquid plastic. This material is petroleum-based products that begins in bead form. To add color, they are spray-painted and then glass coated and tumbled for shine.
Recently materials like Grilamid TR-90 have been developed to answer the need for lightweight and durable frames that offer optical quality not typically associated with typical injection plastics. This new technology has made it possible to make great looking frames that can, in many cases accommodate prescription lenses. A new material, Grilamid TR-90, is a Swiss Nylon Polymer that is melted and then poured into optical quality stainless steel molds. fronts and temples are produced separately. Once removed from the molds, they are hand polished and assembled before the lenses are fitted. The temple tips and nose pieces of many Grilamid TR-90 frames are made from optical grade rubber to add comfort and prevent slippage during strenuous activity. The end result is a frame that is lightweight, yet extremely durable and flexible.
If you’re getting older (like me) you may have noticed Polarized Reading Glasses popping up everywhere. These glasses have a small magnified lens on the bottom of the lens. Some have the polarized film over the entire lens others polarize the non-magnified portion only. Are they for you?
Since I’ve been wearing readers for about three months now, I wanted to review the benefits and disadvantages of using them. First let’s start off with the cons. During my first few days the maginfied potion was distracting when not in use. Along with this they do not have the same field of vision that normal sunglasses provide.
As for the pros, the first benefit is convenience it is wonderful not to have to always have two pairs of glasses (I can never find my reading glasses). After your eyes are trained it’s easy to go from reading to normal viewing they are quite comfortable. Another benefit is stealth, they look like regular sunglasses so people don’t know your using reading glasses. Also by combining your purchase they will also save money.