title: How to buy eyeglasses. Part 1: The eye and its troubles.
mesh_terms: D000328:Adult; D000375:Aging; D002648:Child; D002675:Child, Preschool; D005139:Eyeglasses; D006801:Humans; D007223:Infant; D008875:Middle Aged; D009885:Ophthalmology; D009907:Optometry; D014787:Vision Tests; D014785:Vision, Ocular / Q000502:physiology*