The device comprises a mask (1) held on a persons head (9) with the aid of at least one strap (2) for positioning the mask (1) over the eyes on the forehead part of the head (9) in such a way as to shield the eyes from the surrounding light, the mask (1) being provided with at least one second strap (3, 4) connected to the lateral ends (10, 11) of the mask (1) and intended to pass round the headrest (8) of a chair or of a seat in such a way as to hold the persons head (9) in a position that is aligned anatomically with respect to the axis of the spinal column of the person in a seated position.
