In addition to materials itself, sunglasses lenses should also pay attention to whether the lens is deformed. Deformed sunglasses will affect the viewing effect, and will also have great damage to vision. Of course, to distinguish whether the lens is deformed, we can carefully compare the two lenses of the sunglasses to see if the lens has the same warpage. Then, take the sunglasses 45 cm away from the eyes and observe the vertical and horizontal lines around the glasses. Then move the glasses up and down, such as a straight twist or swing, indicating that the sunglasses lens is deformed, and the myopia lens can also be selected by this method.
