Replacement eyes aren't available at your local Wal-Mart (not yet, anyway), so protect them at all costs. If you wear eyeglasses, ensure the lenses are shatterproof plastic. If you aren't sure, ask your doctor. If you don't wear glasses or if you wear contact lenses, be sure to use eye protection. From full-face shields (for grinding) to simple plastic protective eyeglasses, any protection is better than none at all.