GB711326A - Improvements in or relating to devices for testing and exercising the eyes - Google Patents

Abstract

711,326. Eye testing and exercising apparatus. AMERICAN OPTICAL CO. Aug. 22, 1952, No. 21177/52. Class 97(1) Two targets are viewed by the two eyes and are movable towards or away from the eyes their lateral separation during such movement being determined by two guide members the separations of which, at the ends near to and remote from the observer are separately adjustable. In the form shown the essential parts are carried on a beam 37 pivoted at 36 to an arm 12 and clamped thereto in a selected position by operating a knob 39. The arm 12 is pivoted to the base 11 and. is' clamped by operating a knob 13 whereby a split, non- rotatable tube within a cylindrical bearing at the end of the arm 12 is caused to expand into frictional contact with the bearing. An adjustable chin rest 46 is provided for the patient to view two targets 91 through lenses 45, incorporating base-out prisms, in mounts 44 with holders 48 for supplementary lenses. A lamp 103 illuminates the targets. Each target is carried in a holder, vertically adjustable, by a screw operated by a knot 95, relatively to a member 86. A scale on the back of each holder indicates the extent of the adjustment. Each member 86 is carried by a bracket 84 secured by screws passing through a slot 82, to a member 76 within a tube 75. The tube 75 is secured to a carriage slidable, between adjustable stops 100, on a bar 69 secured to the top of the beam 37 and having a reference mark 99, in the plane of the targets, movable over a centimetre scale with its zero in the plane of the lenses and a dioptre scale with its zero in their focal plane. Each member 76 is axially adjustable on a member 77 and can be clamped to it by a screw 85 the settings being indicated by scales on the members. The two members 77 are connected by a tension spring which urges them together to engage rollers 78, depending from the members through other slots in the tube 75, with bars 62. Each bar 62 is pivoted at 60, in the focal plane of'the lenses 45, to a collar 56 on a tube 49 secured to the beam 37, the collars being equally and oppositely adjustable along the tube by a left-and-right handed screw, within the tube operated by either of the knobs 35 at the ends, the amount of adjustment being indicated by a scale 61. The inner ends of the bars 62 are similarly adjustable by a device within the tube 66 adjustable by knobs 67. This adjustment is indicated by a scale 66a which is read against that one of the graduations of the scale 65a which corresponds to the reading of the scale 61.