what is the difference between photochromic and transition lenses?

What is the cheapest way to buy prescription glasses?

After the examination, you will bring your optometry sheet and go to the optician to match your glasses. Note that the optical shop has professional qualifications. The refractive index of the resin lens, such as 1.49, 1.56, 1.61, 1.67, and so on, mainly depends on the degree. If the degree is not high, 1.56 will do. In addition, the sophisticated store will also measure the nose height, nose width, the distance between the eyes and ears, and the forward angle of the frame, which are also indicators of whether the glasses are comfortable to wear. It is recommended to try them on after they are fitted, and the time to try on them should be longer, so as to determine whether the glasses are suitable.

What Are Progressive Lenses?

Progressive lenses also called multifocal lenses, have three prescriptions in one pair of glasses, which allows you to see near, middle-distance, and far objects without changing your glasses.

The traditional glasses have telltale lines in the lenses, while the progressive lenses are an update on bifocal and trifocal lenses. Progressive lenses have a seamless look. Sometimes, they are called no-line bifocals. The more accurate name is no-line trifocals.

Progressive lenses are typically designed for people over 40 years old who are both nearsighted and farsighted. With the progressive lenses, there is no need for you to change the nearsightedness eyeglasses and the farsightedness eyeglasses constantly.

Go to a regular hospital to check your eyes

On the surface, pseudo-myopia is the same as true myopia, that is, looking far away is blurred and near looking clearly. But looking at the essence through the phenomenon, the difference between the two is obvious. The so-called pseudo-myopia is due to frequent incorrect use of the eyes. The ciliary muscles continue to contract and spasm, and they cannot get the rest. And the crystals are also in a state of thickening. In this way, the parallel light from the outside enters the eye, and after the thickened lens chamber is flexed, the focus falls to the front of the retina, and it is naturally unclear to look at things in the distance. During this period, the eyeball has no organic changes. If you can take proper rest and treatment, pay attention to eye hygiene, use your eyes reasonably, and hope to restore normal vision. However, if the false myopia is not corrected and treated in time, it will develop into true myopia over time. There are many ways to treat pseudomyopia, mainly relaxation and adjustment, such as application of cycloplegia, acupuncture, physical therapy, improving the learning environment, paying attention to eye hygiene, and doing eye exercises. If you suspect false myopia, you should go to the hospital for an eye examination as soon as possible.

Phone can identify polarized sunglasses.

Take a mobile phone with an LCD screen, turn it to maximum brightness, and look at the LCD screen through the lenses. Make sure the lenses are parallel to the display, and then slowly rotate the phone. When the true polarized lens is rotated at a certain angle, the light from the display becomes obviously darker, or even pitch-black. If they're not dark, they're not polarized sunglasses.

What is a progressive lens?

Progressive multifocal lenses are lenses with different upper and lower powers for seeing far above and below for seeing near. The distance from the fixed far power above the lens to the near power fixed below the lens does not change suddenly, but a gradual transition between the two through the gradual change in refractive power. Compared with ordinary lenses, there are many advantages. The appearance of the lens is like a single vision lens, and the dividing line of the power change is not visible. Not only is the appearance beautiful, but more importantly, it protects the age privacy of the wearer, and there is no need to worry about revealing the age secret due to wearing glasses.

Since the change of the lens power is gradual, there will be no image jump. It is comfortable to wear and easy to adapt. So it is easy to be accepted. Because the degree is gradual, the replacement of the adjustment effect is gradually increased according to the shortening of the short distance. There is no adjustment fluctuation, and it is not easy to cause visual fatigue. Clear vision can be obtained at all distances in the visual range.

Such a pair of glasses meets the use of long-distance, near-use and various distances in the middle at the same time. It is especially good news for teachers, doctors, music workers, and computer operators, because these people not only need to see far and near objects clearly, but most of the time they also need to be able to see middle distance objects such as blackboards, piano scores, and computer screens. . This is not possible with any lens other than progressive lenses.

Compared with single vision glasses, bifocals are multi-focal glasses.

Compared with single vision glasses, bifocal glasses, trifocal glasses belong to multi-focus glasses, and the types of trifocal glasses are diverse. When choosing the optical properties of a trifocal lens, it can be thought that the lens is made up of three different lenses: the main lens, the distal optic regions, two appendages. One for the distance and one for the proximal area.