Which index of the lenses should I choose?
In simplicity, 1.56 Index is the most thick, and 1.74 Index is the thinnest.
(±) 0.00 ~ 2.75 |
3.00 ~ 5.75 |
6.00 ~ 7.75 |
8.00 ~ |
1.56 Index |
1.61 Index |
1.67 Index |
1.74 Index |
Please note: the above is just the recommendation, it's not compulsory.
For example, if SPH is -2.00, you still can choose 1.67 index; if SPH is -8.00, you can choose 1.56 index, but it will be very thick