Eye mask can reduce the light intensity and isolate you in a darkness environment, so as to induce your brain into sleep.
Generally, eye mask is all right. But for people with presbyopic, it is not suitable. For people with myopia, wearing eye mask can improve sight by gently impressing eye balls. But for old people, bit by bit the lens of eyes would become harden. If the lens were pressed, its capacity would serious bad.
Many other things can help to sleep, like peaceful music, gentle exercise and reading. If you still wanna an eye mask, purchase one whit cotton fibre, because the skin around eyes are very tender.