Types of Single Vision Lenses
Single vision lenses come in several different types including the 1.59 polycarbonate single vision, 1.57 mid-index single vision and polarized single vision.
1.59 polycarbonate single vision lenses are characterized by their durability and impact resistance. They often include an anti-scratch coating or anti-reflective coating. This lens is much lighter and thinner than a traditional plastic lens, and it blocks the sun’s harmful UV, offering maximum UV protection.
1.57 mid-index single vision lenses are thinner than regular plastic and moderately lighter and stronger. They come with an anti-scratch coating or anti-reflective coating. These lenses are an ideal option for people with relatively higher prescriptions. But they are thicker than the polycarbonate lenses.
Polarized single vision lenses are sunglasses that protect your eyes from light that bounces off smooth, highly reflective surfaces like asphalt, snow, and water. These lenses work by controlling certain light properties and limiting specific wavelengths. They boast a vertical filter that does not allow horizontal glare to pass through.
Have regular professional examinations.
The rimless glasses frame is directly punched on the lens and fasteners are added to fix the lens. It is easy to loosen the lens after long-term wearing. Therefore, it is recommended to regularly check and correct the glasses in the store when wearing rimless glasses. If the protective nut of rimless glasses falls off, stop using them immediately and repair them in time before wearing them. If screws and other accessories are loose, etc, be sure to go to the optical shop by the professional processing division to adjust.
Do You Need Plano Glasses?
Many people choose to wear plano glasses or glasses without prescription just for cosmetic reasons, without any need for vision correction. Normally, glasses frames without a prescription come with a pair of cheap plastic demo lenses.
Since there is no corrective effect on plano glasses, some people choose wear plano glasses for protecting their eyes from dust, and other flying objects. In addition, plano lenses come in a variety of protective coatings - anti-glare, scratch-resistant, blue light coating, UV coating to provide all around protection to the eyes.
So, if you want to protect your eyes from some unexpected damage, you can choose to wear the plano glasses and they would not bring any damage to your eyes.
Shape memory alloy
It is made up of nickel, titanium, vanadium, and other metals, and has good elasticity. When faced with external force, the temple can bend more than BETA titanium alloy and can be restored to the original state, so it is named shape memory alloy.
Half titanium frame: Usually, it refers to the titanium combination frame, such as metal frame with pure titanium or β titanium conveniently. It can be reversed, and the former is more common.
How to know your face shape to choose glasses?
To determine your face shape and spectacle styles that will look best on you, pull your hair away from your face and look directly into a mirror. Look closely at your face and head. You need to measure your forehead width, cheekbone width, jawline width and face length.
After measuring, you need to consider your facial features. There are a few characteristics tied to specific face shapes. For example, a rounder jawline is typically tied to a rounder face shape, a pointed chin is closely related to a heart-shaped face. And you need to take note of the angles and contours of your face to see they are soft or sharp or pronounced or not.
Then you can check whether you have a round shape face, squared face or others.
Round face shape: the forehead round at the hairline; the width of your face is the same as the length; the jawline round with very subtle angles, and the length of your face is the same as the width.
Square face shape: the hairline follows a straight line; there are minimal curves to your cheekbones; you would have a strong and squared jawline.
Diamond face shape: the width of your face is smaller than the width of your cheekbones; the cheekbones significantly wider than your forehead and jawline; you may have a narrow chin area; the length of your face is the same as the width.
There are also other face shapes. You can click here to know more.
The lenses of prescription glasses
Common materials for lenses include glass, resin, and PC. The glass is fragile and heavy, and few people wear it anymore. PC film is tough and not fragile, but it is not resistant to high temperature and the surface is easily scratched. The most common type of lens on the market today is the resin lens, which is light in weight, hard to break, and reasonable in price. At present, it is generally recommended that you choose resin sheets, and it is recommended that people with ultra-high myopia choose glass sheets.
Generally, lenses can be divided into spherical and aspherical surfaces according to different curvature designs. When choosing, refer to the degree of the eye. For people with lower degrees, There are fewer differences between the two shapes. For people with moderate to high myopia, aspherical lenses will have better imaging effects and clearer vision.
When choosing a lens, a parameter that is often mentioned is the refractive index. Common refractive indexes are 1.56, 1.60, 1.67, and 1.74. With the same degree, the higher the refractive index, the thinner the lens.
The hazards of rusty spectacle frames
The most common allergenic metal is nickel. Once allergy occurs, it can cause contact dermatitides such as redness, swelling, itching, and yellow water on the surrounding skin. Many alloy products in daily life contain nickel, such as coins, various alloy products, electroplated objects, spectacle frames, metal watchbands, belt buckles, artificial jewelry, underwear buckles, etc. Their direct contact with the skin will cause allergies to sensitive people. Therefore, the temples and nose pads are the parts that contact the skin with a larger area. In particular, the outer surface of the metal frame and the metal contain a large amount of nickel, which can cause rust spots and skin corrosion, and allergies through contact with the skin and the erosion of sweat.