Color-changing lenses naturally change with the intensity of the light to resist harmful light and protect the eyes. Many people think that color-changing lenses are very convenient for outdoor activities in many cases, and some people think that color-changing lenses are not completely Yes, for this question, let's take a look at whether the photochromic lenses are good or not. From the perspective of the principle of color-changing lenses, the color-changing lenses automatically change color under the light to protect the eyes. It dims when the light is strong, and fades when the light is weak. The main reason is that the crystals of silver in the lens are at work. Under normal circumstances, due to sunlight, the silver in the crystal is in a free state, and will form small aggregates inside the lens, showing irregular blocks, they will absorb light, and the lens will become dark; , the crystal is re-formed, and the lens returns to a bright state. Therefore, it can resist ultraviolet rays and glare, reduce the damage to the eyes due to light, and prevent keratitis, corneal endothelial damage, macular degeneration and other diseases. If you often go out with color-changing lenses, it is not good, and your eyes are prone to fatigue. The pupil becomes larger and smaller with the color of the lens. The pupil of the human eye will automatically become larger in a dark environment. If the pupil has been dilated for a long time, it is easy to cause eye diseases such as glaucoma. The long-term change of the lens is uncertain, and the pupil of the human eye will also be in a long-term change. The color of the lens changes. When the lens becomes brighter, the pupil shrinks; when the lens becomes darker, the pupil expands. The characteristics of this change are in a certain Sometimes it will affect the function of the pupil, so color-changing lenses are not suitable for long-term wear. If the difference between the two eyes is particularly large, the thickness of the photochromic lenses will also be relatively different, and the shades of the lenses will be different when the lens encounters light discoloration, which will also affect the eyes to a certain extent. When necessary, it is better to use a pair of polarized lenses for myopia, that is, myopia lenses inside and sunglasses clips on the outside. When you use it, put the polarizer on (magnet) and you can drink ordinary ones. Wear like glasses.