Simply put, stress refers to the degree of tightness of the lens installed inside the cheapest eyeglasses frame. The tighter the installation, the greater the stress. My glasses don't fit well, is it because I have too much stress when wearing them?
Unless it causes deformation in the central area of the lens, it has no effect. Many experts use a stress gauge to measure the stress on the lens, and a slight increase or decrease in peripheral stress has no effect.
And there are also some situations where installation must be tightened:
- For example, round tortoise shell glass frames with astigmatism: The circular frame lenses are easy to rotate inside. If they are not tight, the lenses may rotate after prolonged wear. If there is astigmatism, it can cause inaccurate axis positioning and blurred vision;
- The degree is relatively high, and it usually needs to be installed tighter. High degree discountglasses lenses will be thicker and heavier, so safety considerations must be more important. There is nothing more dangerous than a lens falling off.
However, there are also situations where it cannot be too tight: the sheet frame cannot be too tight, as it may experience thermal expansion and contraction. If installed too tightly, it can easily cause the lens to bulge and deform over time, affecting vision and comfort.
How to self-check lens stress: Find a tube lamp, then look at the reflection on the lens towards the tube lamp, move the lens from top to bottom, and the shape of the tube lamp should be uniform. If the central area of the lens tube light is not deformed, it is not a problem, and even if there is slight deformation at the edge position, it is not a problem.
