Sure can, in fact you can change the colour of peoples eyes completely! Use the Color brick, then sample the iris (for example) with the eye dropper, then select Brush Color In from the drop down gear menu in the Color brick. Paint the irises then adjust hue, saturation etc to suit. My model now has one brown eye and one bright green.
Most of the adjustment bricks now have this really useful Brush xx In command and it really allows you to be very selective and creative. AP3 is a massive step forward in my opinion, it's just a shame so many folks are having install problems - we never get to hear the success stories of course, such is the nature of a help forum.
Have fun
FlatE 🙂