Standard progressive lenses are multifocal lenses with three observation areas, farsightedness, intermediate vision, and nearsightedness. Unlike bifocals, there are no visible lines between each viewing area. They have a seamless, invisible design, where the optical power changes 'gradually' throughout the lens. Many people confuse 'bifocal' or 'trifocal' with 'progressive' but remember that bifocals and trifocals have visible lines in the lens, while progressive lenses do not. Because progressive lenses have no lines in the lens, they are more popular multifocal lenses than bifocal lenses.
The main observation area of the progressive lens is a far distance, the smaller area at the bottom of the lens is used for myopia, and the middle area in the middle is smaller. Standard progressive glasses are very suitable for general purpose glasses, focusing on hyperopia activities (such as driving and walking) and sufficient area in the lenses for nearsighted activities (such as reading and computer use). The left and right sides or 'convex corners' of the lens are deliberately blurred to achieve an invisible design. The clearest line of sight in the gradual process is from the center to the top of the lens.
Features of Beta titanium glasses frame
Beta titanium has better strength, fatigue resistance, and environmental corrosion resistance than pure titanium and other titanium alloys. The shape plasticity is very good, which can be made into wire and sheet, more lightweight. They are used to make glasses and can get more shapes and styles. It's the material for a new generation of glasses. Customers with higher requirements for style and weight can completely choose beta-titanium glasses. Because β titanium processing technology is higher than pure titanium, usually only large factories and brands will produce, and the price is higher than pure titanium glasses.
The first inventor of wearable glasses is not known. However, it was the Romans who first discovered the use of glass to enhance their ability to see small words, creating small magnifying glasses with spheres. The first known wearable glasses in history appeared in Italy in the 13th century. They were used mainly by monks, and became popular little by little during the Renaissance, as the technology improved. As their popularity grew, the Italian glasses spread throughout Europe, mostly within reach of the wealthy. Because learning was a prized attribute during the Renaissance, glasses were a status symbol of wisdom and prosperity. With the temple extending above the ear, the glasses are no longer required by hand.
How are we nearsighted?
The light from external objects to the eye needs to be refracted by the lens before it can be imaged on the retina. The refractive power of the lens depends on the contraction and relaxation of the ciliary muscle. When we look at close objects, the ciliary muscles contract and the lens becomes thicker. When we look at distant objects, the ciliary muscles relax and the lens becomes thinner. Adjust the focal length of near and far objects so that they will show a clear image on the retina. If you use your eyes too often and the longer the ciliary muscles work continuously, the ciliary muscles will spasm because of too much tension. At this time, the lens cannot be adjusted and thinned. After the light from a distant object is refracted by the lens, the imaging position will fall in front of the retina instead of on the retina. Only a blurred image can be seen, which becomes myopia.
There is another situation. For some people, due to genetic factors, in the process of growth and development, the front and rear wheelbase of the eyeball will gradually become longer. In this way, although the adjustment function of the ciliary muscle and the lens is normal, the image formed will also fall in front of the retina due to the longer the axis distance of the eyeball, which can also cause myopia.
The two causes of myopia are different. Myopia caused by ciliary muscle spasm is called 'pseudo-myopia'. As long as the ciliary muscles are relaxed, myopia can be reversed. Myopia caused by the extension of the wheelbase of the front and back of the eyeball is called 'true myopia', which cannot be reversed and can only be corrected by myopia glasses.
Blue Light Glasses Benefits
As mentioned above, blue light glasses are good for our eyes. What are the other benefits of blue light glasses?
1.Reduce Eye Strain
One of the benefits of blue light glasses is reducing eye strain. Looking at a screen all day can make you feel stressed, or you may experience eye and muscle strain. So, the blue light blocking glasses can help to reduce eye strain.
Blue light has a high frequency which can increase alertness and delay the body’s release of melatonin. So, you had better turn off your device an hour or two before going to bed. Or you can choose to wear a pair of blue light glasses to sleep better.
Wearing blue light glasses can effectively help you to reduce headaches.
4.Fewer Eye Diseases
A large amount of blue light is bad for our health. So, wearing blue light glasses can reduce the chance of eye diseases.
With so many blue light glasses benefits, do you want to get a pair of blue light blocking glasses? If so, you can try the Koalaeye Optical blue light blocking glasses. It enables you to wear comfortable and look in style at a reasonable price.
How to buy prescription glasses online
Consumers should choose different styles of frames according to their age and professional characteristics. Because everyone has different face shapes, different interpupillary distances, and different diopters, the size of the frames should vary from person to person.
Lenses are divided into glass lens, resin lens, and PC lens, and you can choose according to your preferences. The glass lens has a stable refractive index, good abrasion resistance, and stable optical performance, but it is relatively heavy and easy to break. Resin lens with high light transmittance is light, safe, and not easy to break, but the surface is easy to wear. PC lens has a high refractive index, but the surface is easy to wear.
Glasses Size - Lens Height
Lens height is the length between the top edge of a lens and the bottom edge of that lens. Lens height is the distance between the lowest point of the lens and the top of the frame above it. This number may be influenced by the style of your glasses.