Posts Tagged ‘optical eyeglasses’

A Simple Guide To Choose Optical Glasses Online

November 8th, 2011

Optical glasses, otherwise known as prescription eyeglasses, are the ones that have vision correction capabilities and are often used as a means to improve people’s eyesight. They are a pretty important aid for those who suffer from various vision problems, helping them through the most basic tasks on a daily basis. It is fatally important that you get a pair that is immaculately tuned and that fits you just fine for once you got the prescription of your glasses wrong, everything else in your life is bound to follow suit. Traditionally, optical glasses are bought and sold in stores and at malls, but recently, like just about any other commodity that was once only transacted offline, more and more purchases of optical eyeglasses are done online, at the comfort of the buyer’s home and with the convenience of merely clicking of mouse. Although buying glasses online is no longer considered a novel matter, there does exist some common rules you need to remember when you tend to have your eyeglasses updated online.


The first step toward getting an ideal pair of optical eyeglasses is to have your eyes fully and minutely checked at a professional’s. And when you leave the door, don’t forget to take your prescription with you, because that’s what you need to land the perfect glasses on the Internet. For any optical glasses wearer, it’s a matter of life and death to get his prescriptions right, for without the appropriate prescription, all the subsequent efforts on materials and styles will all go in vain. Once you have your prescription powers clear, you can go online and do a search on websites or optical stores that sell such glasses.

When you get to the place where you intended to go, make sure to find the optical glasses category first. Normally, an online optical store would provide anything from shades to optical glasses. Sometimes, it is tagged under prescription glasses or RX glasses. If you find such tags, don’t worry, they are basically the same thing. Next, you need to find the wanted prescription and after that, there are two things that need to be addressed. One is eyeglass lenses, and the other glasses frames. When one chooses glasses online, he needs to decide is he wants rosin lenses or glass ones. Nowadays, glasses lenses have gradually been replaced by rosin ones for their better durability. However, there are still lenses made in glass for those who are particularly in favor of such material. As for frames, optical glasses can come in numerous styles, and it is matter of pure personal taste what you choose. So, have your prescription chosen exactly and lenses and frames chosen based on your special condition and you will find yourself on the right rack toward getting the ideal pair.


The principle of optical eyeglasses

January 26th, 2010

Modern eyeglasses are frames with two lenses worn in front of the eyes. The eyeglasses are usually braced by pads on the bridge of the nose and temples placed over the ears. Eyeglasses are normally designed for the purpose of vision correction, eye protection, viewing visual information or fashion and aesthetic values. Optical eyeglasses are designed mainly for vision correction.

Optical eyeglasses’ frames are commonly made from metal or plastic. And the lenses of optical eyeglasses can be made from glass or transparent plastic, such as CR-39 or polycarbonate. Whatever kind of materials the lenses made from, the principle of optical eyeglasses is similar.

The optical eyeglasses’ lens is an optical device with perfect or approximate axial symmetry which can converge or diverge the light.

Most optical eyeglasses are spherical lenses, the two surfaces of which are parts of the surfaces of spheres, with the lens axis ideally perpendicular to both surfaces. Lenses are classified by the curvature of the two optical surfaces. The two surfaces of the lens can be both convex, both concave, one flat and one convex, one flat and one concave, or with one convex and one concave. The last one, called convex-concave or meniscus, is the type of lens that is most commonly used in optical eyeglasses.

Optical eyeglasses can be either positive or negative, depending on the curvatures of the two surfaces. Negative optical eyeglasses have steeper concave surfaces and will be thinner at the centre than at the periphery. This type of optical eyeglasses is used for correcting nearsightedness. Conversely, positive optical eyeglasses have steeper convex surfaces and will be thicker at the centre than at the periphery, and it is for presbyopia.