Why is a prescription for glasses different from a prescription for contact lenses?
The frame glasses degrees are the optometric degrees of the eye, and the difference between the frame glasses degrees and the contact lens degrees is mainly due to the different contact distances between the two lenses and the eye. Usually, degrees of contact lenses and glasses need to be converted by a professional through vertex diopter. The conversion formula is Fc=Fs/(1-d×Fs). In the formula, Fc is the diopter of contact lens, Fs is the diopter of glasses frame lens, and D is the distance between frame glasses lens and cornea. Assuming that the prescription of frame glasses is -4.00d and the distance between lens apex is 12mm, the prescription of contact lenses is -4.00/ [1-0.012×(-4.00)] = -3.82d.
Choose the right color for your safety glasses.
If you work in a dazzling environment, do high-precision work, or work indoors and outdoors, you may need different types of colors. The right color will help your eyes adapt to the conditions and reduce the amount of focus and refocus your eyes need. If the color of safety glasses is not used correctly, eye strain may result.
How to Choose Reading Glasses?
Find the right power. When choosing reading glasses, finding the right power would be the most important thing. All reading glasses will have signs or stickers indicating their power. In most cases, they will range from +1 to +4 diopter, in increments of +0.25. So, when choosing reading glasses, try the lowest power first.
Test-drive the glasses. If you have brought reading material with you, try reading it at a comfortable length. If you hold the material too far out to be able to read it, you should increase the power. Keep testing the differences powers until can read clearly at the distance that’s more comfortable for you.
How to Choose Glasses for Long Face?
Bold shapes and eyeglasses with decorative details are also a smart choice since they help draw attention to your eyes and can add width to your face. Be sure to avoid narrow or rectangular shapes, which can make your face appear longer.
Square glasses: if you have a long face, you can try square glasses whose sharper corners can help to balance out the length of your face and complement your narrow features. Choose frames that are slightly wider than your cheekbones to make your face appear broader.
Two-toned glasses: if you have a long face shape, the two-toned glasses would be a good choice. The color-top frames create an optical illusion that draws focus upward toward your eyes rather than to the length of your face.
How To Choose Better Night Driving Glasses?
Driving at night has a high accident rate because of poor visibility, blinding headlights, and fatigue. Now the market exists a few main glasses: sunglasses polarizing lenses, Glasses that use or mimic the first generation of patented technology. So how do you compare the options between driving and wearing glasses?
Night driving lens is relatively special compared with daily driving lens, not only to prevent strong light and see the road more clearly. According to the national motor vehicle driver special glasses standards, QBT 2659-2004 daily light transmittance should be more than 8%, night light transmittance should be more than 75%. Be sure to consult customer service. Ask about the situation. Note that a pair of polarized sunglasses are not suitable for use at night, and the light transmittance must reach the national safety standards.
What Are Trifocal Lenses?
When you are over 40 years old, your eyes may become old, too. Your corrective lens requirements may become increasingly unique, Most people are familiar with bifocal glasses but unfamiliar with trifocal glasses. So, in this post, we will show you what trifocal glasses are.
Trifocal lenses have three different corrective lenses within one lens to offer you intermediate, distance, and near correction, all in one pair of glasses. The varying levels of correction cab are laid out in a couple of different ways to ensure the layout suits your unique vision needs and comfort level.
The near vision is to correct close-up vision, the intermediate vision is often used for card playing and staring at the computer screen fall with this range of vision, and the distance vision is often used for driving or looking at a whiteboard.
This unique pattern is the perfect choice for those who want to wear tops and jackets of any color. They fit almost any color. Tortoise glasses come in many colors, and this stylish pattern has a wide palette, so there's no need to worry about skin and hair color. If you want to keep up with current eyewear trends, unique-patterned tortoiseshell glasses are your best bet.