Aids for the partially sighted.
D000367:Age Factors; D001296:Audiovisual Aids; D001766:Blindness / Q000209:etiology / Q000534:rehabilitation*; D003261:Contact Lenses; D005139:Eyeglasses; D006801:Humans; D007360:Intelligence; D007909:Lenses; D009042:Motivation; D014787:Vision Tests; D014785:Vision, Ocular