Without posting a base curve chart, we will generalize the base curve selection. We begin with a plano lens. The base curve would most likely fall around 6 base. Going in the plus Rx direction- the base curve goes “higher”: 7 base, 8 base, 10 base. Going in the minus Rx direction – the base curve decreases: 5 base, 4 base, 2 base, plano base.
The lens style and manufacturer play a role in the selection. The progressive lens style is a good example. Different manufacturers use different base curves. The original assumption of where an Rx falls on a base curve chart remains.
Base curve selection differs with aspheric lens designs. Generally the base is reduced, flattened, compared to a spheric design.
Example Rx: +3.00 spheric lens-> 8 base
+3.00 aspheric design->4 base