what is sph and cyl?

How long do plastic frames last?

Plastic frames are made of non-biodegradable materials and are possible to last forever. If the frame is made of acetate, the layers of acetate fibers make the frame vary in degrees of transparency and pattern. The plastic frame manufacturing process makes the plastic frame more brittle than the acetate frame. In this sense, the acetate frame has a longer service life. Then the plastic, which is made of SAP, will never break down. Depending on the circumstances, it could take years. If the lenses are polycarbonate, the material takes hundreds of years to break down naturally. If TR-90 is normally stored, not exposed to the sun, and put in the box with cloth wrapped, and then you can keep 3 years, there is no effect.

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.

Semi-rimless glasses are easier to clean and maintain

Semi-rimless glasses usually have only half of the glass frame. We tend to wipe our glasses in one direction, but we all know that the glasses are all wrapped up. So when some small particles appear on our glasses, these things can not be wiped out by the glasses cloth, and it is easy to scratch the lens. This is one of the drawbacks of full-frame glasses.

What difference do mono-focal glasses and multi-focal glasses have?

A mono-focal lens is a lens with one focal point. Usually, the myopic far-sighted presbyopia that we see belongs to mono-focal glasses. There is only one diopter on one lens, and this is the single focal point. Multi-focal glasses are lenses that have multiple focal points, that is, multiple diopters. Both mono-focal glasses and multi-focal glasses are visual correction tools, but mono-focal glasses can meet basic vision needs, like fatigue relief, control of depth of diopters, and focus on different distances such as the need to see far and near.But because there are many different diopters on a multi-focal glasses lens, so the elderly can not only see far after wearing. When they see close distance, they do not need to take off glasses or wear reading glasses. Wearing multi-focal glasses is not easy to fatigue.

Confirm the optometric data

It is necessary to confirm the accuracy of optometric data. If you stay up late or look at the phone or computer for too long before the optometry, leading to visual fatigue, it will increase the degree. But if you can let your eyes have a good rest, and then take optometry, the degree may be restored to the original situation, so you need to know the state of optometry, to check if it really had increased in degrees. The main purpose of progressive lens is to use it for people who have bleached eyes and often take off the lens.

New Fashion Police Men's Polarized Sunglasses Driving Glasses

They have high quality. The lens material is a polarized lens. The frame color is silver/gold/brown/black and the visibility rate is 99(%). UV protection rating is UV400,with 100% UV protection. They are suitable for driving, fishing, daily leisure.

Most accidents happen at night and before dawn, which has a lot to do with glare and the problem of many people having blurred vision in the dark. Every driver knows the trouble of driving at night: glare, bright reflections, and bright lights from oncoming traffic. In addition, poor visibility at night can make driving tiring and dangerous!

Benefits of wearing blue light blocking glasses

1. Use blue light blocking glasses to relieve eye discomfort.

Excessive use of the device can cause computer vision syndrome or digital eye fatigue. Glasses with blue light filtering technology can enhance your concentration and reduce eye fatigue, thereby making your eyes feel less tired and improving work efficiency. Another way to reduce eye strain is to ensure that you stay away from the screen regularly.

2. Sleep better with blue light blocking glasses

One of the more surprising effects of touching the screen is that it may have a negative effect on sleep patterns. Blue light has a high energy frequency, which can increase alertness and delay the body's release of melatonin, which helps induce sleep. Generally speaking, we should all avoid using Blu-ray devices one to two hours before going to bed. Anti-blue light glasses can reduce the impact of blue light, allowing you to use your device before going to bed and still have a good night's sleep. However, the best option is to put down the screen before going to bed.

3. Reduce the possibility of AMD

Age-related macular degeneration (AMD) is the main cause of blindness. Anti-blue light lenses can help avoid or delay this situation by preventing blue light from affecting your eyes.

Computers, TVs, mobile phones, and tablets all emit blue light. Even with long-term exposure, the blue light emitted by these devices may not be enough to cause damage to the eyes or vision. However, further research is needed to confirm whether the blue light emitted from these devices is harmful. Experts are also uncertain whether blue light glasses can help symptoms associated with increased screen exposure. Ophthalmologists suggest that eye fatigue, headaches, and lack of sleep may be related to computer vision syndrome, rather than blue light exposure. For eye health, wearing blue light blocking glasses is not enough, we still have to develop good eye habits.