Permanent Green Light vs Lime Green

How close are they?

ΔE 25.1, loose: different enough that you should pick on purpose. Lime Green is much more muted, warmer than Permanent Green Light.

Can I use Lime Green instead of Permanent Green Light?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 25). Lime Green is much more muted, warmer than Permanent Green Light.

Can I use Permanent Green Light instead of Lime Green?

The same difference applies the other way round: Permanent Green Light is much more saturated, cooler.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.