Eye colours are usually texture maps and not easily changed in Poser.

However, you can mix and match textures for each figure.  For example, I use Vicky 3 lots, and I sometimes use a head morph from one package, a body morph from another, a skin texture from a different one and eyes and lip colour from others.  I sometimes even cross textures from Akio to V3 because  those 2 figures are compatible with each other for textures.

So if you have other texture/character packs for JessieG2, you can pick and choose between other texture packages made for JessieG2.

Also, why not go back to Content Paradise and redownload the eye colours and reinstall them?

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi