Is it permissible for an elderly woman to uncover her hair when going out?

An elderly woman is not permitted to uncover her hair when going out. It is permissible for her to lighten the outer garments that do not expose the awrah, if she has reached such an old age that she is generally not desired. This is after her head is covered. It is permissible for her to uncover her face and hands, although covering them is more preferable.