Abstract: An optical device comprising a wearing member to be attached to the body of the user, a first lens holder provided on the wearing member and having attached thereto a pair of eyepiece concave lenses as spaced apart by an adjustable distance, and a second lens holder connected to the wearing member or to the first lens holder and having attached thereto a pair of objective convex lenses as spaced apart by an adjustable distance. Accordingly, the distance between the eyepiece concave lenses and the distance between the objective convex lenses are adjustable each independently of the other to position the optical center of each lens accurately on the visual axis of the corresponding eye of the user.

Abstract: The invention provides spectacles in which the distance between two lens frames (1)(2) is variable and which has holders (7)(7a) on the lens frame, a bridge (8) slidably fitted in the holder for connecting the lens frames together and holding means (9) for determining the effective length of the bridge.