I know everybody is more afraid of the flash of a flintlock than they are the pop of a percussion cap, but in my experience you are more likely to receive eye damage from a caplock than you are a flintlock. The only time I truly thought I had lost an eye, was when shooting a Remington Zouave replica a piece of scalding hot cap landed on my eyelid ( and they say flinching, and blinking, won't save you) and stuck to it. So, when my eyes went wide with surprise and pain, the hot cap fragment rolled up in the eyelid. If that doesn't get you into eye protection nothing will.
Hungry Horse