Spectacles and Eyeglasses/Index

INDEX.

• Adjustment of eyeglasses, 97
  • of spectacles, 91
• Airy, discoverer of astigmatism, 23
• Alhazen, 19
• Ancient glass, 17
• Angle, deviating, of a prism, 84, 89
  • refracting, 84, 87
• Apex of a prism, finding the, 83
• Assyrians, knowledge of lenses among, 18
• Astigmatism, discovery of, 23
• Asymmetry of the face, 97

• Bar spring eyeglasses, 46
• Bifocal glasses, 42
  • invention of, 23
  • varieties of, 44
• Brewster, Sir David, 18, 23
• Bridge, width of base of, 73
  • relation of top of to plane of glasses, 58, 72
  • height of, 71
• Bridges, manufacture of, 38
  • varieties of, 40

• Care of spectacles, 100
• Cemented bifocals, 44
• Centering and decentering, 49
  • normal lateral, 55
  • normal vertical, 56
  • of spectacles for constant use, 55
    • near work, 55, 57
• Centrad, 53, 85, 86, 90
• Chemical composition of glass, 29
• Component parts of spectacles, 27
• Conformation of nose pieces, 98
• Crown glass, 29
• Cylinder, finding the axis of, 81

• Date of invention of spectacles, 20
• Decentered lenses, 50
  • prismatic effect of, 51
• Deviating angle of a prism, 84, 89
• Dioptric system, 33
• Di Spina, Alessandro, 20
• Discovery of astigmatism, 23
• Distance between the pupils, 51, 67
  • between temples, 94
  • of the glasses from the eyes, 57

• Emerald used by Nero, 18
• Epicanthus, eyeglasses for, 48
• Eyeglasses, advantages and disadvantages of, 26
  • inspection and adjustment of, 76, 97
  • prescription of, 75
  • varieties of, 46
• Extra front, 45
• Eye wires, manufacture of, 38

• Face, asymmetry of, 70, 74, 97
• Facing of spectacles, 58
• Focal length of lenses, 76
• Frames (see spectacle frames)
• Frameless spectacles, 39
• Franklin, inventor of bifocal glasses, 23
  • glasses, 42

• Geometrical center, 49
• Glass, chemical composition of, 29
  • ancient, 17
• Ground bifocals, 44

• Height of bridge, 71
• Hook temples, 38, 95

• Index of refraction, 30
• Inspection and adjustment of spectacles, 76
• Interpupillary distance, 51, 65, 67
• Introduction, 17
• Invention of spectacles, 20
• Irregularity of surface of lenses, 91

• Kepler, Johann, 22

• Lateral centering, 55
• Lathe for grinding lenses, 34
• Lens cutter, 35
  • oldest known, 18
• Lenses, decentered, 50
  • finding focal length of, 76
  • forms of, 30
  • known to the ancients, 18
  • material of, 28
  • method of grinding, 34
  • neutralization of spherical, 79
    • cylindrical, 80
    • sphero-cylindrical, 81
  • numeration of, 33
  • proving the strength of, 76
  • toric, 37, 63
  • tilted, 58
• Locating the optical center, 82
• Lorgnettes, 26

• Maddox pupil localizer, 69
• Marking of gold spectacle frames, 27
• Material of lenses, 28
  • of spectacle frames, 26
• Meniscus, 31

• Natural position for spectacle bridge, 57
• Nero, concave jewel used by, 18
• Neutralization of spherical lenses, 79
  • cylindrical lenses, 80
  • sphero-cylindrical lenses, 81
• New system of numbering lenses, 33
• Normal position of spectacles, 49
• Nose pieces, conformation of, 98
• Numeration of lenses, 33
  • of prisms, 84

• Offset guard, 46
• Oldest known lens, 18
• Old system of numbering lenses, 33
• Opticians' lathe, 34
• Optical center, 49
  • locating the, 82

• Pebble spectacles, 29
• Periscopic glasses, 36, 62
• Pince nez (see eyeglasses)
• Phacometers, 77
• Plane of the glasses, relation to the visual axis, 58
• Prism diopter, 84
  • finding the apex of, 83
  • deviating angle of, 84, 89
  • refracting angle of, 84, 87
  • numeration of, 84
• Prismatic effect of decentering, 51
• Prismetry, 87
• Prescription blank for spectacles, 67
  • of eyeglasses, 75
  • of frames, 65
• Proving the strength of lenses, 76
• Principal axis, 49
• Principles of spectacle fitting, 49
• Pupil localizer, 69
• Pupillometer, 70

• Quizzing glasses, 26

• Refracting angle of a prism, 84, 87
  • surfaces, 30
• Rigid frame eyeglasses, 46
• Rock crystal, 18, 29
• Romans, knowledge of lenses among, 18
• Rule for measuring frames, 65

• Saddle bridge, 40
• Salvinus Armatus, 20
• Scratches, specks, flaws, etc., in glass, 90
• Signs used in prescription writing, 32
• Spectacle eyes, sizes of, 42
  • • shapes of, 41
  • fitting, principles of, 49
  • frames, adjustment of, 91
  • material of, 26
  • marking of gold, 27
  • prescription of, 65
  • rule for measuring, 65
• Spectacles, component parts of, 27
  • bifocal, 42
• Spectacles, care of, 100
  • date of invention of, 20
  • early references to, 20, 21
  • for cosmetic effect, 48
  • invention of bifocal, 23
  • inspection and adjustment of, 76
  • frameless, 39
  • facing of, 58
  • patterns of, 38
  • pebble, 29
  • periscopic, 36, 62
  • reversible, 40
• St. Jerome's eyeglasses, 21
• Surface, irregularity of, 91

• Temples, distance between, 94
• Temples, manufacture of, 38
  • varieties of, 40
• Tilted lenses, 58
• "Tool" for grinding spherical lenses, 35
• Tools for adjusting frames, 91
• Toric lenses, 37, 63
• Transparent glass found in Nineveh, 17
• Trial frames, 69, 74

• Vertical centering, 56
• Visual axis, relation of plane of the glasses to, 58

• Width of base of bridge, 73