How to buy contact lenses online?
Choose well-known brands.Nowadays, the contact lens brands in the market are mixed, with the proliferation of inferior products, but there are still some authoritative and well-known ones, like Johnson & Johnson, Bausch & Lomb, which are products recognized by most users, and you can rest assured to buy them.
Why Are My Progressive Lenses Blurry?
Progressive lenses are optical lenses designed for simultaneous correction of far, medium and near. Progressive lenses use polishing technology to achieve a gradual transition between the two focal lengths. With progressive lenses, people do not have to switch their glasses for different purposes.
However, with the usage of progressive lenses, there are some problems of progressive voices. One of the most commonly reported side effects of progressive lenses is blurry or fuzzy peripheral vision. The blurriness is usually most noticeable through the lower portion of the lens and to the left and right of near and immediate zones.
Types of aspheric lenses
There are two types of aspheric lenses: single aspheric surface (single aspheric surface for short, different from the outer aspheric surface and inner aspheric surface) and double aspheric surface (double aspheric surface for short). For the outer aspheric surface, convex is an aspheric surface and concave is a spherical surface. For the inner aspheric surface, a convex surface is a sphere, and a concave surface is an aspheric surface. In addition to correcting aberrations, the double aspheric lens also improves the effective field of vision compared to the single aspheric surface. When people's eyes look through the edge of the lens to see things, like driving when looking at the reflective mirror, it often affects vision because of the large aberration at the edge of the lens. Previous designs of aspheric plates have analyzed a single ray of light passing through the center of the pupil. Wavefront technology controls the entire beam of light passing through the pupil, eliminating high-order aberrations.
Are polarized glasses good for fishing?
Fishing goggles are polarized lenses. Fishing goggles are a type of goggles that can remove scales on the surface of the water so that the fisherman can see the fish taking the bait. Polarized sunglasses increase color saturation and prevent eye strain. Wear gray glasses on sunny days when fishing. They can fully absorb infrared rays, as well as most ultraviolet rays, without changing the original color of the scene. Warm, natural colors are a popular lens choice. Wear green glasses on cloudy days when fishing. like gray glasses, they can absorb all the lone infrared rays and 99% of the ultraviolet rays, but sometimes the color of the scene after passing through the green lens will be changed. But because green brings a cool and refreshing feeling, it is also good for eye protection.
The extraction of titanium
Nowadays, the commonly used extraction method is the reduction method of titanium tetrachloride. Compared to copper and zinc, although high in content, much more expensive. On the other hand, China is the country with the largest reserves of titanium, and a large number of steel mills with perennial overcapacity began to produce titanium, so the price of titanium fell year after year.
Why do you need to adjust your glasses?
After wearing glasses for a period of time, the frames will become deformed and loose. Due to the deformation of the frame, the wearer may experience blurred vision, dizziness, visual fatigue, and other symptoms, the glasses need to be adjusted regularly. And because the shape of each person's face and the relative position of nose and ears are different, you need to adjust your glasses according to your own features. To make wearing comfortable, glasses do not overpress the nose and ears. After wearing glasses, it is advisable to have no tenderness at the contact point and not to slide down the head frame. The frames have to be made fundamental adjustments after assembly to meet fundamental standards.
The Types of Blue Light Glasses
Computer Glasses - Clear Lenses
First, we will show you the computer glasses which have clear lenses, These glasses are made to be used when working on your computer, smartphone or while watching TV. The best computer glasses can filter 5-30% of all blue light.
Night Driving Glasses - Yellow Lenses
When driving at night, the blue light glasses with yellow lenses would be suitable. These blue light lenses are good at removing more of the highest energy blue light, around 440 nm and they are also able to distinguish traffic lights when driving at night. These glasses can block around 65-70% of blue light.
Blue Light Glasses for Sleeping - Red Lenses
The blue light glasses for sleeping have red lenses. The best blue light glasses come with red lenses and they block 99.5%-99.9% of all blue light and a large amount of the green light spectrum, from 495-550 nm.
After knowing the different types of blue light glasses, we will show you how to perform the blue light glasses tests.