How to choose proper lens according to different prescription?

[Millie]

Which index lens should I choose If I have -5.00 in both eyes?

[Deanna]

If your prescription is lower than -3.00, the standard 1.5 index lens will be ok and won't be too thick. If the prescription is between -3.00 and -5.00, you can choose index of 1.56 to 1.59. Prescription stronger than -5.00 should choose index lens over 1.60.

[Araceli]

Your prescription is not so strong. People who have prescription strength from -300 to -500 can choose the 1.56 to 1.59 lens, which can fit your power properly.