Anti Radiation Aspheric Prescription CR-39 Resin Lenes

How to choose lens index Lens index reflects lens thickness, there is 1.56, 1.61, 1.67 index etc. The higher lens index is, the thinner lens is. 1.67 is thinner than 1.61 than 1.56 at the same degree. Lens thickness also depends on frame size. The bigger frame is, the thicker lens is.   1.56 index suggestion degree: SPH: -0.00 ~ -4.00;CYL: -0.50~-2.00 SPH: +0.50~+4.00;CYL:+0.50~+2.00   1.61 index suggestion degree: SPH: -0.00 ~ -6.00;CYL: -0.50~-2.00  SPH: +4.00~+6.00;CYL:+0.50~+2.00   1.67 index suggestion degree: SPH: -3.00 ~ -8.00;CYL: -0.50~-2.00  SPH: +4.00~+8.00;CYL:+0.50~+2.00    1.74 index suggestion degree: SPH: -3.00 ~ -10.00;CYL: -0.50~-2.00 If your Cylinder＞2.00, you need to pay extra 10usd for high astigmatism customization.  ($10 link here)   If you have any question, please contact with us  ( service@cinily.net )