MY EYE FELL OUT!!!
Step 1: Materials
This costume doesn't take much effort, and I only needed to buy one thing...
The optic nerve is made of wool, the bandage is a proper eye-bandage (it's "out of date", donated to the boys by a first-aider friend), and the whole thing is held together with PVA glue.
Extra effects were applied with a touch of Kitewife's blusher.
Step 2: Attaching the optic nerve to the eye.
The eyeball is the only thing I bought - I had gone to the store looking for a ping pong ball to decorate, but a bag of ten plastic eyeballs for 99p could not be resisted, and saved me stretching my artistic skills beyond their limit.
The optic nerve is made of a bunch of red yarn - I used eight pieces a few inches long. They got trimmed later.
I held the eyeball still*, and drew an eight-pointed star of glue on the eyeball. The position of the star is supposed to make sure that the iris of the eyball will be visible later.
Starting at the points of the star, I laid the yarn on the glue from point to the centre of the star, so that the strands come together to form the optic nerve.
When it was dry, I braided the strands of yarn together into one optic nerve. Simply twisting doesn't work, because it untwists.
*You have no idea how weird it is to clamp an eyeball in a bench vice...
Step 3: Attaching the nerve to the patch
Work out how long you want the nerve to be (how far down your face you want it to dangle, then knot it off and trim off the excess yarn.
I glued the nerve to the inside of the eyepatch with a blob of PVA, but you could sew it instead. I just didn't want stitches showing through.
When you glue the nerve in place, be aware of which way round the eyeball hangs, and glue the side of the nerve that make the iris face outwards.
Weight the nerve down while it dries - I stood the bottle of glue on the patch.