Refractive index of spectacle lens
It is generally believed that the higher the refractive index, the better the spectacle lens. Such spectacle lenses are relatively thin, and of course, the price is a bit expensive. When the refractive index increases, the direction of the light entering the lens will change greatly, the focus will move to the lens, the focal length will be smaller, and the diopter will become larger. In order to keep the diopter unchanged, it is necessary to reduce the curvature of the lens, that is, to reduce the curvature of the mirror surface, so that the thickness of the lens can be reduced. This is why the larger the refractive index, the thinner the lens is. Under the same premise of other things, the larger the refractive index, the thinner the lens, the lighter and more beautiful the lens, and the higher the price, but the larger the refractive index is not the better.
Advantages Of TR90 Frames
- Lightweight. The weight is about half the weight of the plate frame, which can reduce the burden on the bridge of the nose and ears, and it is also comfortable to wear for a long time.
- Bright colors. Compared with ordinary plastic frames, the color of TR90 frames is even better.
- Impact resistance. The TR90 frame is extremely flexible, and its good elasticity can effectively prevent damage to the eyes caused by impact during sports.
Regardless of whether it is a sheet frame or a TR90 frame, they have their own advantages. You can choose them according to your requirements, Importantly, it is comfortable to wear and good-looking.
Why do you need to wear safety goggles correctly?
Eye strain occurs when muscles are tired from strenuous exercise (from tension to concentration), similar to what happens to other muscles in the body from strenuous exercise or overuse. Eyestrain is the result of eye pain and fatigue, often accompanied by headaches. Eye strain has a lot to do with the quality of your glasses. If you wear cheap and inferior safety glasses for hours at work, you will feel uncomfortable. While your eyes won't be permanently damaged by fatigue, it can affect your productivity.
What Is Photophobia?
There are a lot of reasons causing our eyes discomforts, such as moving between indoors and outdoors on bright sunny days, staring at computer screens all day, driving at night, or watching TV. If the discomfort worsens over time with accompanying symptoms such as intense pain, excessive squinting, excessive tearing or burning sensations, it may become an eye condition called photophobia or light sensitivity.
One of the symptoms of photophobia is intolerance of light. To some degree, most of us are sensitive to bright or fluorescent lights, but those suffering from photophobia may experience a range of symptoms - from minor or mild irritation to serious debilitating reactions. The symptoms can include dizziness, headaches, migraines, server eye pain, excessive blinking, blurriness, and eye inflammation.
So, they are a few ways to combat photophobia.
Sunglasses For Fishing - Oyea
Oyea is a well-known eyewear brand in China. Headquartered in Xiamen City, Fujian Province, Oyea eyewear is a diversified company integrating design, development, production, and sales. Oyea classifies the products carefully to meet the different needs of customers so that customers have more choices. The brand is the pioneer and leader of sports glasses in China, focusing on the development and sales of eyewear categories. The appearance of this brand filled the blank in the field of domestic sports glasses and opened a brand new situation of category.
The history of chromatic contact lenses
Chromatic contact lenses, commonly known as color Lens, is a kind of Soft hydrophilic Contact Lens, belongs to the third category of medical devices. In 1971, Bausch & Lomb introduced the world's first pair of soft contact lenses. Before this, contact lenses are made of hard materials, with poor comfort, difficult to promote. Soon after, CIBA Vision made the lenses aqua blue to make them easier for users to operate. There were also special contact lenses with dark loops on the lenses, which were designed to help people with injured or defective eyes, like corneal white spots or iris defects, to conceal flaws, forming artificial pupils, so they were called beauty lenses.
Then, in the 1980s, American company Wesley Jessen (later bought by VisiCon) introduced the FreshLook chromatic contact lens, which used laser technology to print colored patterns onto the lens to change the color of the wearer's iris. Since then, contact lenses have been developed from a simple vision correction tool into a cosmetic with the effect of beauty makeup. It can brighten, enlarge, darken or change the color of the iris of the eye. At present, the common chromatic contact lenses are black, brown, gray, purple, blue, green, and so on. There are also a variety of color combinations or some special patterns.
What To Do with Old Glasses?
What to do with old glasses? Where can I donate old glasses? You may have the same troubles. So, in this section, we will show you what you should do with your old glasses.
You can choose to donate your old glasses. Around the world, about 13 million children can’t finish their education for the sole reason that they can’t see well enough to learn. In addition, there are some goodwill organizations that will take your used reading glasses as long as they are in decent shape. So, what to do with old glasses, donate them. Where can I donate old glasses? You can search the old glasses donation organizations online.
If you have a pair of old glasses, you can also choose to sell them online to save some money. You can sell them on some platforms such as eBay or Preloved.