65m/m Minus Front Base Round

Tri-focal 8x20x36 (Extra Thick)

(8 is Intermediate, 20 is Segment, and 36 is Total)

 

Semi-Finished

Material: CR-39*

Base Curves: -3.00

 

Additions: 2.00, 2.50, 3.00, 3.50, 4.00, 4.50, 5.00, 5.50, 6.00, 6.50, 7.00, 7.50, 8.00, 8.50, 9.00, 9.50, 10.00

 

Material: CR-39* Plastic                                                                       Specific Gravity: 1.32

Index of Refraction: 1.498                                                                          Minus Front Base

Abbe Value: 58                                                                                                      8x20x36

                                                                                                                   Round Tri-focal

 

Minus Front Base Tri-Focal
8m/m - 20m/m - 8m/m = 36m/m

EXTRA THICK

 

Lens         Actual         Nominal      Actual             Back           Sag                                               Seg        Seg

Style         Size                  Curve       Curve           Curve       50m/m         C.T.           E.T.           Inset      Drop

-Base

Tri-focal   65m/m               -3.00          -3.12               2.75         1.831         17.0           22.0               0.0        2.5