1. It is very important to check the UV label on the lens.

According to the F·D·A standard, the lens must filter out more than 90% of the ultraviolet rays in the sun

while ensuring the light transmittance.

The lens should be labeled with "UV-100PROTCT10N".

When filtering 100% of UV rays, the label "UV-400PROTCT10N" should be affixed.

2. Lenses cannot have the "power" that only optical lenses have.

Generally, if the diopter exceeds 15%, you will feel dizzy when wearing it.

3. The lens must have high strength and pass the impact resistance test.

Generally speaking, the strength of plastic sheets (propionic acid or cellulose acetate), resin sheets, and glass sheets increases from small to large.